ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (1,409,091)
  • Articles: DFG German National Licenses  (1,409,091)
  • Springer  (1,409,091)
  • MDPI Publishing
Collection
  • Articles  (1,409,091)
Source
Keywords
Publisher
Years
Topic
  • 1
    Electronic Resource
    Electronic Resource
    Forward jet production in deep inelastic scattering at HERA (2006)
    Springer
    The European physical journal 46 (2006), S. 27-42 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The production of forward jets has been measured in deep inelastic ep collisions at HERA. The results are presented in terms of single differential cross sections as a function of the Bjorken scaling variable (xBj) and as triple differential cross sections d3σ/dxBjdQ2 $dp_{t,{\rm jet}}^2$ , where Q2 is the four momentum transfer squared and $p_{t,{\rm jet}}^2$ is the squared transverse momentum of the forward jet. Also cross sections for events with a di-jet system in addition to the forward jet are measured as a function of the rapidity separation between the forward jet and the two additional jets. The measurements are compared with next-to-leading order QCD calculations and with the predictions of various QCD-based models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02471-x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Effective-Lagrangian approach to γγ→WW II: Results and comparison with e+e-→WW (2006)
    Springer
    The European physical journal 46 (2006), S. 93-105 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: AbstractWe present a study of anomalous electroweak gauge-boson couplings that can be measured in e+e- and γγ collisions at a future linear collider like ILC. We consider the gauge-boson sector of a locally SU(2)×U(1) invariant effective Lagrangian with ten dimension-six operators added to the Lagrangian of the standard model. These operators induce anomalous three-gauge-boson and four-gauge-boson couplings and an anomalous γγH coupling. We calculate the reachable sensitivity for the measurement of the anomalous couplings in γγ→WW. We compare these results with the reachable precision in the reaction e+e-→WW on the one hand and with the bounds that one can obtain from high-precision observables in Z decays on the other hand. We show that one needs both the e+e- and the γγ modes at an ILC to constrain the largest possible number of anomalous couplings and that the Giga-Z mode offers the best sensitivity for certain anomalous couplings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2006-02474-1
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    A remark on the motivic Galois group and the quantum coadjoint action (2006)
    Springer
    The European physical journal 46 (2006), S. 269-275 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: AbstractIt has been suggested that the Grothendieck–Teichmüller group GT should act on the Duflo isomorphism of su(2), but the corresponding realization of GT turned out to be trivial. We show that a solvable quotient of the motivic Galois group – which is supposed to agree with GT – is closely related to the quantum coadjoint action on $U_q(sl_2)$ for q a root of unity, i.e. in the quantum group case one has a nontrivial realization of a quotient of the motivic Galois group. From a discussion of the algebraic properties of this realization we conclude that in more general cases than $U_q(sl_2)$ it should be related to a quantum version of the motivic Galois group. Finally, we discuss the relation of our construction to quantum field and string theory and explain what we believe to be the ‘physical reason’ behind this relation between the motivic Galois group and the quantum coadjoint action. This might be a starting point for the generalization of our construction to more involved examples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2006-02487-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    New result on the measurement of the direct photon emission in K+→π+π0γ decay (2006)
    Springer
    The European physical journal 46 (2006), S. 61-67 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: AbstractWe present a new result on the K+→π+π0γ decay measurement using stopped kaons. The best fit to the decay spectrum comprised of 10 k events gives a branching ratio for the direct photon emission of [3.8±0.8 (stat)±0.7 (syst)]×10-6 in the π+ kinetic energy region of 55 to 90 MeV. This result has been obtained with the assumption that there is no component due to interference with the inner bremsstrahlung.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2006-02492-y
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    The QCD pomeron in ultraperipheral heavy ion collisions: V. Double vector meson production in the BFKL approach (2006)
    Springer
    The European physical journal 46 (2006), S. 219-224 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: AbstractIn this work the double vector meson production in ultraperipheral heavy ion collisions is investigated within the BFKL approach. The integrated cross sections and event rates for the processes $AA\rightarrow V_1 V_2 AA$ ( $V_i=\rho, \omega, \phi, J/\Psi, \Upsilon$ ) are computed and theoretical estimates for scattering on both light and heavy nuclei are given for energies of RHIC and LHC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2006-02473-2
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Ultra low momentum neutron catalyzed nuclear reactions on metallic hydride surfaces (2006)
    Springer
    The European physical journal 46 (2006), S. 107-111 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: AbstractUltra low momentum neutron catalyzed nuclear reactions in metallic hydride system surfaces are discussed. Weak interaction catalysis initially occurs when neutrons (along with neutrinos) are produced from the protons that capture “heavy” electrons. Surface electron masses are shifted upwards by localized condensed matter electromagnetic fields. Condensed matter quantum electrodynamic processes may also shift the densities of final states, allowing an appreciable production of extremely low momentum neutrons, which are thereby efficiently absorbed by nearby nuclei. No Coulomb barriers exist for the weak interaction neutron production or other resulting catalytic processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2006-02479-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Transversity and its accompanying T-odd distribution from Drell–Yan processes with pion-proton collisions (2006)
    Springer
    The European physical journal 46 (2006), S. 147-150 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: AbstractThis paper studies the possibility of direct extraction of the transversity and its accompanying T-odd parton distribution function (PDF) from Drell–Yan (DY) processes with unpolarized pion beam and with both unpolarized and transversely polarized proton targets. At present, such an extraction can be performed with the COMPASS experiment at CERN. The preliminary estimations performed for the COMPASS kinematic region demonstrate that it is quite realistic to extract both transversity and its accompanying T-odd PDF under COMPASS conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2006-02490-1
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    A measurement of the tau hadronic branching ratios (2006)
    Springer
    The European physical journal 46 (2006), S. 1-26 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: AbstractThe exclusive and semi-exclusive branching ratios of the τ lepton hadronic decay modes ( $h^- \nu_\tau$ , $h^- \pi〈Superscript〉0〈/Superscript〉 \nu_\tau$ , $h^-\pi^0 \pi^0\nu_\tau$ , $h^- \geq2 \pi^0 \nu_\tau$ , $h^- \geq3 \pi^0 \nu_\tau$ , $2h^- h^+ \nu_\tau$ , $2h^- h^+\pi^0\nu_\tau$ , $2h^- h^+ \geq2 \pi^0 \nu_\tau$ , $3h^- 2h^+\nu_\tau$ and $3h^- 2h^+ \geq1 \pi^0 \nu_\tau$ ) were measured with data from the DELPHI detector at LEP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2006-02494-9
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Unintegrated gluon distributions and Higgs boson productionin proton-proton collisions (2006)
    Springer
    The European physical journal 46 (2006), S. 123-134 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Inclusive cross sections for Higgs boson production in proton-proton collisions are calculated in the formalism of unintegrated gluon distributions (UGDFs). Different UGDFs from the literature are used. Although they were constructed in order to describe the HERA deep-inelastic scattering F2 data, they lead to surprisingly different results for Higgs boson production. We present both the two-dimensional invariant cross section as a function of Higgs boson rapidity and transverse momentum, as well as the corresponding projections on rapidity or transverse momentum. We quantify the differences between different UGDs by applying different cuts on interrelations between the transverse momentum of the Higgs and the transverse momenta of both fusing gluons. We focus on the large rapidity region. The interplay of the gluon-gluon fusion and weak-boson fusion in rapidity and transverse momentum is discussed. We find that above pt ∼ 50–100 GeV the weak-gauge boson fusion dominates over gluon-gluon fusion.PACS. 12.38.Bx,12.38.Cy,13.85.Qk,14.70.Hp,14.80.Bn
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02464-9
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    The Dalitz decay π0 → e+e– γ revisited (2006)
    Springer
    The European physical journal 46 (2006), S. 191-217 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The amplitude of the Dalitz decay π0 → e+e– γ is studied and its model-independent properties are discussed in detail. A calculation of radiative corrections is performed within the framework of two-flavor chiral perturbation theory, enlarged by virtual photons and leptons. The lowest meson dominance approximation, motivated by large NC considerations, is used for the description of the π0 –γ*–γ* transition form factor and for the estimate of the NLO low energy constants involved in the analysis. The two photon reducible contributions are included and discussed. Previous calculations are extended to the whole kinematical range of the soft photon approximation, thus allowing for the possibility to consider various experimental situations and observables.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02466-7
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Anaerobic Bioremediation of Groundwater Containing a Mixture of 1,1,2,2-Tetrachloroethane and Chloroethenes (2006)
    Springer
    Biodegradation 17 (2006), S. 193-206 
    Details
    ISSN: 1572-9729
    Keywords: bioremediation ; Dehalococcoides ; dechlorination ; microcosm ; tetrachloroethane ; trichloroethene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This study investigated the biotransformation pathways of 1,1,2,2-tetrachloroethane (1,1,2,2-TeCA) in the presence of chloroethenes (i.e. tetrachloroethene, PCE; trichloroethene, TCE) in anaerobic microcosms constructed with subsurface soil and groundwater from a contaminated site. When amended with yeast extract, lactate, butyrate, or H2 and acetate, 1,1,2,2-TeCA was initially dechlorinated via both hydrogenolysis to 1,1,2-trichloroethane (1,1,2-TCA) (major pathway) and dichloroelimination to dichloroethenes (DCEs) (minor pathway), with both reactions occurring under sulfidogenic conditions. In the presence of only H2, the hydrogenolysis of 1,1,2,2-TeCA to 1,1,2-TCA apparently required the presence of acetate to occur. Once formed, 1,1,2-TCA was degraded predominantly via dichloroelimination to vinyl chloride (VC). Ultimately, chloroethanes were converted to chloroethenes (mainly VC and DCEs) which persisted in the microcosms for very long periods along with PCE and TCE originally present in the groundwater. Hydrogenolysis of chloroethenes occurred only after highly reducing methanogenic conditions were established. However, substantial conversion to ethene (ETH) was observed only in microcosms amended with yeast extract (200 mg/l), suggesting that groundwater lacked some nutritional factors which were likely provided to dechlorinating microorganisms by this complex organic substrate. Bioaugmentation with an H2-utilizing PCE-dechlorinating Dehalococcoides spp. -containing culture resulted in the conversion of 1,1,2,2-TeCA, PCE and TCE to ETH and VC. No chloroethanes accumulated during degradation suggesting that 1,1,2,2-TeCA was degraded through initial dichloroelimination into DCEs and then typical hydrogenolysis into ETH and VC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10532-005-4218-7
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Impacts of Bioremediation Schemes on Bacterial Population in Naphthalene-Contaminated Marine Sediments (2006)
    Springer
    Biodegradation 17 (2006), S. 227-235 
    Details
    ISSN: 1572-9729
    Keywords: community fingerprint ; polycyclic aromatic hydrocarbon ; 16S rRNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Microcosm experiments were conduced in which the surface of marine sediment was contaminated with naphthalene and subjected to either of three different bioremediation schemes, i.e., biostimulation (BS) by supplementing with slow-release nitrogen and phosphorus fertilizers, bioaugmentation (BA) by inoculating with Cycloclasticus sp. E2, an aromatics-degrading bacterium identified to play an important role for aromatic-hydrocarbon degradation in marine environments and combination (CB) of BS and BA. These three schemes were found to be similarly effective for removing naphthalene, while naphthalene disappearance in sediment without any treatment (WT) was slower than those in the treated sediments. Shifts in bacterial populations during and after bioremediation were analyzed by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA gene fragments. It was found that the Cycloclasticus rRNA type occurred as the strongest bands in the course of naphthalene degradation. Clustering analysis of DGGE profiles showed that bacterial populations in the WT, BS and CB sediments differed consistently from those in the uncontaminated control, while the profile for the BA sediment was finally included in the cluster for uncontaminated control sediments after a 150-day treatment. The results suggest that bioaugmentation with ecologically competent pollutant-degrading bacteria is an ecologically promising bioremediation scheme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10532-005-5018-9
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Isolation of Fenitrothion-degrading Strain Burkholderia sp. FDS-1 and Cloning of mpd Gene (2006)
    Springer
    Biodegradation 17 (2006), S. 275-283 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; Burkholderia ; fenitrothion ; mpd gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A short rod shaped, gram-negative bacterium strain Burkholderia sp. FDS-1 was isolated from the sludge of the wastewater treating system of an organophosphorus pesticides manufacturer. The isolate was capable of using fenitrothion as the sole carbon source for its growth. FDS-1 first hydrolyzed fenitrothion to 3-methyl-4-nitrophenol, which was further metabolized to nitrite and methylhydroquinone. The addition of other carbon source and omitting phosphorus source had little effect on the hydrolysis of fenitrothion. The gene encoding the organophosphorus hydrolytic enzyme was cloned and sequenced. The sequence was similar to mpd, a gene previously shown to encode a parathion-methyl-hydrolyzing enzyme in Plesiomonas sp. M6. The inoculation of strain FDS-1 (106 cells g−1) to soil treated with 100 mg fenitrothion emulsion kg−1 resulted in a higher degradation rate than in noninoculated soils regardless of the soil sterilized or nonsterilized. These results highlight the potential of this bacterium to be used in the cleanup of contaminated pesticide waste in the environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10532-005-7130-2
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    2,4-Dichlorophenoxyacetic Acid (2,4-D) Utilization by Delftia acidovorans MC1 at Alkaline pH and in the Presence of Dichlorprop is Improved by Introduction of the tfdK Gene (2006)
    Springer
    Biodegradation 17 (2006), S. 263-273 
    Details
    ISSN: 1572-9729
    Keywords: Delftia acidovorans MC1 ; 2,4-dichlorophenoxyacetic acid (2,4-D) ; 2-(2,4-dichlorophenoxy) propanoic acid (2,4-DP) ; effect of tfdK gene ; simultaneous utilization of 2,4-D and 2,4-DP ; uptake characteristics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Growth of Delftia acidovorans MC1 on 2,4-dichlorophenoxyacetic acid (2,4-D) and on racemic 2-(2,4-dichlorophenoxy)propanoic acid ((RS)-2,4-DP) was studied in the perspective of an extension of the strain’s degradation capacity at alkaline pH. At pH 6.8 the strain grew on 2,4-D at a maximum rate (μmax) of 0.158 h−1. The half-maximum rate-associated substrate concentration (Ks) was 45 μM. At pH 8.5 μmax was only 0.05 h−1 and the substrate affinity was mucher lower than at pH 6.8. The initial attack of 2,4-D was not the limiting step at pH 8.5 as was seen from high dioxygenase activity in cells grown at this pH. High stationary 2,4-D concentrations and the fact that μmax with dichlorprop was around 0.2 h−1 at both pHs rather pointed at limited 2,4-D uptake at pH 8.5. Introduction of tfdK from D. acidovorans P4a by conjugation, coding for a 2,4-D-specific transporter resulted in improved growth on 2,4-D at pH 8.5 with μmax of 0.147 h−1 and Ks of 267 μM. Experiments with labeled substrates showed significantly enhanced 2,4-D uptake by the transconjugant TK62. This is taken as an indication of expression of the tfdK gene and proper function of the transporter. The uncoupler carbonylcyanide m-chlorophenylhydrazone (CCCP) reduced the influx of 2,4-D. At a concentration of 195 μM 2,4-D, the effect amounted to 90% and 50%, respectively, with TK62 and MC1. Cloning of tfdK also improved the utilization of 2,4-D in the presence of (RS)−2,4-DP. Simultaneous and almost complete degradation of both compounds occurred in TK62 up to D = 0.23 h−1 at pH 6.8 and up to D = 0.2 h−1 at pH 8.5. In contrast, MC1 left 2,4-D largely unutilized even at low dilution rates when growing on herbicide mixtures at pH 8.5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10532-005-6894-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Efforts to Explain and Control the Prolonged Thermophilic Period in Two-phase Olive Oil Mill Sludge Composting (2006)
    Springer
    Biodegradation 17 (2006), S. 285-292 
    Details
    ISSN: 1572-9729
    Keywords: composting ; crude oil ; olive mill wastewater ; olive oil mills ; olive tree branches ; olive tree leaves ; sludge ; woodchips
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The aim of this paper was to evaluate the use of different bulking agents in different ratios as a means to control, optimise and eventually reduce the duration of the thermophilic period in two-phase olive oil mill sludge (OOMS) composting. The bulking agents used were: (i) olive tree leaves (OTL), (ii) olive tree shredded branches (OTB) and (iii) woodchips (WDC). The selection of these materials was based on their abundance and availability on the island of Crete, the southernmost point of Greece. The ratios studied were: Pile 1, OOMS:OTL in 1:1 v/v; Pile 2, OOMS:WDC in 1:1.5 v/v; Pile 3, OOMS:OTL in 1:2 v/v; Pile 4, OOMS:OTL:OTB in 1:1:1 v/v; and Pile 5, OOMS:OTL:OTB in 1:1:2 v/v. The composting system used was that of windrows with the volume of each pile approximately 20–25 m3. The experiments took place over two consecutive years. A composting turner was used and turnings were performed at one and two week intervals. In each pile a variety of physiochemical parameters were monitored. Temperature remained high in all five trials. Piles 1, 2, 3, 4 and 5 temperatures recorded values of above 50 °C for 106, 158, 160, 175 and 183 days, respectively. Volumes were reduced by approximately 67%, 62%, 63%, 80% and 84%, respectively. Temperature remained high, mainly due to the presence in large amounts of oily substances which during their complete oxidation release important amounts of energy and aid the cometabolism of more stable molecules such as lignin. This process is better described as the slow “burning” of a “fuel” mixture in an “engine” than composting. This approach is based on the extensive similarities of this process to that of crude oil sludge or similar waste composting.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10532-005-7566-4
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Lorentz symmetry breaking and planar effects from non-linear electrodynamics (2006)
    Springer
    The European physical journal 46 (2006), S. 247-254 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: AbstractWe propose a modification of standard linear electrodynamics in four dimensions, where effective non-trivial interactions of the electromagnetic field with itself and with matter fields induce Lorentz violating Chern–Simons terms. This yields two consequences: it provides a more realistic and general scenario for the breakdown of Lorentz symmetry in electromagnetism and it may explain the effective behavior of the electromagnetic field in certain planar phenomena (for instance, Hall effect). A number of proposals for non-linear electrodynamics is discussed along the paper. Important physical implications of the breaking of Lorentz symmetry, such as optical birefringence and the possibility of having conductance in the vacuum are commented on.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2006-02483-0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Production properties of $K^\star(892)^\pm$ vector mesons and their spin alignment as measured in the NOMAD experiment (2006)
    Springer
    The European physical journal 46 (2006), S. 69-79 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: AbstractFirst measurements of $K^\star(892)^\pm$ mesons production properties and their spin alignment in $\nu_\mu$ charged current (CC) and neutral current (NC) interactions are presented. The analysis of the full data sample of the NOMAD experiment is performed in different kinematic regions. For ${K^\star}^+$ and ${K^\star}^-$ mesons produced in $\nu_\mu$ CC interactions and decaying into $K^0 \pi^\pm$ we have found the following yields per event: $(2.6\pm0.2(\text{stat.})\pm0.2(\text{syst.}))\%$ and $(1.6\pm0.1(\text{stat.})\pm0.1(\text{syst.}))\%$ respectively, while for the ${K^\star}^+$ and ${K^\star}^-$ mesons produced in $\nu\text{NC}$ interactions the corresponding yields per event are: $(2.5\pm0.3(\text{stat.})\pm0.3(\text{syst.}))\%$ and $(1.0\pm0.3(\text{stat.})\pm0.2(\text{syst.}))\%$ . The results obtained for the $\rho_{00}$ parameter, $0.40\pm0.06(\text{stat.})\pm0.03(\text{syst.})$ and $0.28\pm0.07(\text{stat.})\pm0.03(\text{syst.})$ for $K^\star(892)^+$ and $K^\star(892)^-$ produced in $\nu_\mu$ CC interactions, are compared to theoretical predictions tuned on LEP measurements in $e^+e^-$ annihilation at the $Z^0$ pole. For $K^\star(892)^+$ mesons produced in $\nu\text{NC}$ interactions the measured $\rho_{00}$ parameter is $0.66\pm0.10(\text{stat.})\pm0.05(\text{syst.})$ .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2006-02500-4
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Generalized gauge theories with nonunitary parallel transport: * General relativity with cosmological constant as an example (2006)
    Springer
    The European physical journal 46 (2006), S. 255-267 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. In gauge theories parallel transporters (PTs) $\mathcal{U}(C)$ along paths C play an important role. Traditionally they are unitary or pseudoorthogonal maps between vector spaces. We propose to abandon unitarity of parallel transporters and with it the a priori assumption of metricity in general relativity. A *-operation on parallel transporters serves as a substitute for it, and this *-operation is proven to be unique on group theoretical grounds. The vierbein and the spin connection appear as distinguishable parts of a single de Sitter gauge field with field strength F. The action takes the form $\frac{3}{16\pi G\Lambda}\int\text{tr}(\boldsymbol{F}\wedge\boldsymbol{F}i\boldsymbol{\gamma}_{5})$ and both the Einstein field equations with arbitrarily small but nonvanishing cosmological constant Λ and the condition of vanishing torsion are obtained from it. The equation of motion for classical massive bodies turns out to be de Sitter covariant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02443-2
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Supersymmetry parameter analysis: SPA convention and project (2006)
    Springer
    The European physical journal 46 (2006), S. 43-60 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. High-precision analyses of supersymmetry parameters aim at reconstructing the fundamental supersymmetric theory and its breaking mechanism. A well defined theoretical framework is needed when higher-order corrections are included. We propose such a scheme, Supersymmetry Parameter Analysis SPA, based on a consistent set of conventions and input parameters. A repository for computer programs is provided which connect parameters in different schemes and relate the Lagrangian parameters to physical observables at LHC and high energy e + e- linear collider experiments, i.e., masses, mixings, decay widths and production cross sections for supersymmetric particles. In addition, programs for calculating high-precision low energy observables, the density of cold dark matter (CDM) in the universe as well as the cross sections for CDM search experiments are included. The SPA scheme still requires extended efforts on both the theoretical and experimental side before data can be evaluated in the future at the level of the desired precision. We take here an initial step of testing the SPA scheme by applying the techniques involved to a specific supersymmetry reference point.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02460-1
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Tree-unitarity bounds for THDM Higgs masses revisited (2006)
    Springer
    The European physical journal 46 (2006), S. 81-91 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: AbstractWe have reconsidered theoretical upper bounds on the scalar boson masses within the two-Higgs-doublet model (THDM), employing the well-known technical condition of tree-level unitarity. Our treatment provides a modest extension and generalization of some previous results of other authors. We present a rather detailed discussion of the solution of the relevant inequalities and offer some new analytic formulae as well as numerical values for the Higgs mass bounds in question. A comparison is made with the earlier results on the subject that can be found in the literature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2006-02472-3
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Evaluating massive planar two-loop tensor vertex integrals (2006)
    Springer
    The European physical journal 46 (2006), S. 157-178 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: AbstractUsing the parallel/orthogonal space method, we calculate the planar two-loop three-point diagram and two rotated reduced planar two-loop three-point diagrams. Together with the crossed topology, these diagrams are the most complicated ones in the two-loop corrections necessary, for instance, for the decay of the Z0 boson. Instead of calculating particular decay processes, we present a new algorithm which allows us to perform arbitrary next-to-next-to-leading order (NNLO) calculations for massive planar two-loop vertex functions in the general mass case. All integration steps up to the last two are performed analytically and will be implemented under xloops as part of the Mainz xloops-GiNaC project. The last two integrations are done numerically using methods like VEGAS and Divonne. Thresholds originating from Landau singularities are found and discussed in detail. In order to demonstrate the numerical stability of our methods we consider particular Feynman integrals which contribute to different physical processes. Our results can be generalized to the case of the crossed topology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2006-02478-9
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Stationary phase corrections in the process of bosonization of multi-quark interactions (2006)
    Springer
    The European physical journal 46 (2006), S. 225-233 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: AbstractThe functional integration over the auxiliary bosonic variables of cubic order related with the effective action of the Nambu–Jona–Lasinio model with ’t Hooft term has recently been obtained in the form of a loop expansion. Even numbers of loops contribute to the action, while odd numbers of loops are assigned to the measure. We consider the two-loop corrections and analyse their effect on the low-lying pseudoscalar and scalar mass spectra, quark condensates and weak decay constants. The results are compared to the leading order calculations and other approaches.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2006-02488-7
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Dual parameterization of generalized parton distributions and a description of DVCS data (2006)
    Springer
    The European physical journal 46 (2006), S. 151-156 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: AbstractWe discuss a new leading-order parameterization of generalized parton distributions of the proton, which is based on the idea of duality. In its minimal version, the parameterization is defined by the usual quark singlet parton distributions and the form factors of the energy-momentum tensor. We demonstrate that our parameterization describes very well the absolute value, the Q2-dependence and the W-dependence of HERA data on the total DVCS cross section and contains no free parameters in the HERA kinematics. The parameterization suits the low-xBj region especially well, which allows us to advocate it as a better alternative to the frequently used double distribution parameterization of the GPDs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2006-02491-0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Flavor coupled with chiral oscillations in the presence of an external magnetic field (2006)
    Springer
    The European physical journal 46 (2006), S. 113-122 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: AbstractReporting to the Dirac wave-packet prescription where it is formally assumed the fermionic nature of the particles, we shall demonstrate that chiral oscillations implicitly aggregated to the interference between positive and negative frequency components of mass eigenstate wave-packets introduce some small modifications to the standard neutrino flavor conversion formula. Assuming the corresponding spinorial solutions of a ‘modified’ Dirac equation, we are specifically interested in quantifying flavor coupled with chiral oscillations for a fermionic Dirac-type particle (neutrino) non-minimally coupling with an external magnetic field B . The viability of the intermediate wave-packet treatment becomes clear when we assume B orthogonal/parallel to the direction of the propagating particle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2006-02502-2
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Screening of heavy quark free energies at finite temperatureand non-zero baryon chemical potential (2006)
    Springer
    The European physical journal 46 (2006), S. 179-189 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We analyze the dependence of heavy quark free energies on the baryon chemical potential μb in 2-flavor QCD by performing a 6th order Taylor expansion in the chemical potential which circumvents the sign problem. The bare quark mass at $\hat m / T = 0.4$ corresponds to a pion mass of about 770 MeV and is thus not in the range of physical quark masses but the quark mass dependence is known to be small above Tc. At Nτ = 4 the lattices are coarse, however, we are using improved (p4 staggered) fermions. The Taylor expansion coefficients of color singlet and color averaged free energies are calculated and from this the expansion coefficients for the corresponding screening masses are determined. We find that for small μb the free energies of a static quark-antiquark pair decrease in a medium with a net excess of quarks and that screening is well described by a screening mass which increases with increasing μb. The μb-dependent corrections to the screening masses are well described by perturbation theory for T ≳ 2Tc. In particular, we find for all temperatures above Tc that the expansion coefficients for singlet and color averaged screening masses differ by a factor 2.PACS. 11.15.Ha, 11.10.Wx, 12.38Gc, 12.38.Mh
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02462-y
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    On bound states of photons in noncommutative U(1) gauge theory (2006)
    Springer
    The European physical journal 46 (2006), S. 235-245 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We consider the possibility that photons of noncommutative U(1) gauge theory can make bound states. Using the potential model, developed based on the constituent gluon picture of QCD glue-balls, arguments are presented in favor of the existence of these bound states. The basic ingredient of the potential model is that the self-interacting massless gauge particles may get mass by the inclusion of non-perturbative effects.PACS. 02.40.Gh, 11.10.Nx, 12.20.-m
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02465-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    High energy evolution of soft gluon cascades (2006)
    Springer
    The European physical journal 46 (2006), S. 135-145 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. In this paper we derive an evolution equation for the gluon density in soft gluon cascades emitted from any colored source, in the leading logarithmic approximation of perturbative QCD. We show that this equation has the same form as the BFKL equation in the forward case. An explicit expression for the total cascade wavefunction involving an arbitrary number of soft gluons is obtained. Renormalization of the colored source wavefunction turns out to be responsible for the reggeization of the source.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02468-5
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    The Impact of Bioaugmentation on Metal Cyanide Degradation and Soil Bacteria Community Structure (2006)
    Springer
    Biodegradation 17 (2006), S. 207-217 
    Details
    ISSN: 1572-9729
    Keywords: biodegradation ; DGGE ; K2Ni(CN)4 soil bacterial populations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Metal cyanides are significant contaminants of many soils found at the site of former industrial activity. In this study we isolated bacteria capable of degrading ferric ferrocyanide and K2Ni(CN)4. One of these bacteria a Rhodococcus spp. was subsequently used to bioaugment a minimal medium broth, spiked with K2Ni(CN)4, containing 1 g of either an uncontaminated topsoil or a former coke works site soil. Degradation of the K2Ni(CN)4 was observed in both soils, however, bioaugmentation did not significantly impact the rate or degree of K2Ni(CN)4 removal. Statistical analysis of denaturing gradient gel electrophoresis profiles showed that the topsoil bacterial community had a higher biodiversity, and its structure was not significantly affected by either K2Ni(CN)4 or bioaugmentation. In contrast, profiles from the coke works site indicated significant changes in the bacterial community in response to these additions. Moreover, in both soils although bioaugmentation did not affect rates of biodegradation the Rhodococcus spp. did become established in the communities in broths containing both top and coke works soil. We conclude that bacterial communities from contaminated soils with low biodiversity are much more readily perturbed through interventions such as contamination events or bioaugmentation treatments and discuss the implications of these findings for bioremediation studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10532-005-4219-6
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Isolation and Characterization of a Pseudomonas Oleovorans Degrading the Chloroacetamide Herbicide Acetochlor (2006)
    Springer
    Biodegradation 17 (2006), S. 219-225 
    Details
    ISSN: 1572-9729
    Keywords: acetochlor ; degradation ; isolation ; Pseudomonas oleovorans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract To date, no pure bacterial cultures that could degrade acetochlor have been described. In this study, one strain of microorganism capable of degrading acetochlor, designated as LCa2, was isolated from acetochlor-contaminated soil. The strain LCa2 is Pseudomonas oleovorans according to the criteria of Bergey’s manual of determinative bacteriology and sequence analysis of the partial 16S rRNA gene. Optimum growth temperature and pH were 35 °C and 8.0, respectively. The strain could degrade 98.03% of acetochlor treated at a concentration of 7.6 mg l−1 after 7 days of incubation and could tolerate 200 mg l−1 of acetochlor. When the acetochlor concentration became higher, the degradation cycle became longer. The acetochlor biodegradation products were identified by GC–MS based on mass spectral data and fragmentation patterns. The main plausible degradative pathways involved dechlorination, hydroxylation, N-dealkylation, C-dealkylation and dehydrogenation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10532-005-4220-0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Bioremediation by Composting of Heavy Oil Refinery Sludge in Semiarid Conditions (2006)
    Springer
    Biodegradation 17 (2006), S. 251-261 
    Details
    ISSN: 1572-9729
    Keywords: bioremediation ; composting ; ecotoxicity ; oil sludge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The present work attempts to ascertain the efficacy of low cost technology (in our case, composting) as a bioremediation technique for reducing the hydrocarbon content of oil refinery sludge with a large total hydrocarbon content (250–300 g kg−1), in semiarid conditions. The oil sludge was produced in a refinery sited in SE Spain The composting system designed, which involved open air piles turned periodically over a period of 3 months, proved to be inexpensive and reliable. The influence on hydrocarbon biodegradation of adding a bulking agent (wood shavings) and inoculation of the composting piles with pig slurry (a liquid organic fertiliser which adds nutrients and microbial biomass to the pile) was also studied. The most difficult part during the composting process was maintaining a suitable level of humidity in the piles. The most effective treatment was the one in which the bulking agent was added, where the initial hydrocarbon content was reduced by 60% in 3 months, compared with the 32% reduction achieved without the bulking agent. The introduction of the organic fertiliser did not significantly improve the degree of hydrocarbon degradation (56% hydrocarbon degraded). The composting process undoubtedly led to the biodegradation of toxic compounds, as was demonstrated by ecotoxicity tests using luminescent bacteria and tests on plants in Petri dishes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10532-005-5020-2
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    The ACCEL Model for Accelerating the Detoxification Kinetics of Hydrocarbons Requiring Initial Monooxygenation Reactions (2006)
    Springer
    Biodegradation 17 (2006), S. 237-250 
    Details
    ISSN: 1572-9729
    Keywords: activated sludge ; dichlorophenol ; monooxygenation ; nicotinamide adenine dinucleotide ; phenolics ; specific growth rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The two-tank accelerator/aerator modification of activated sludge significantly increases the biodegradation of hydrocarbons requiring initial monooxygenation reactions, such as phenol and 2,4-dichlorophenol (DCP). The small accelerator tank has a controlled low dissolved oxygen (DO) concentration that can enrich the biomass in NADH + H+. It also has a very high specific growth rate (μacc) that up-regulates the biomass’s content of the monooxygenase enzyme. Here, we develop and test the ACCEL model, which quantifies all key phenomena taking place when the accelerator/aerator system is used to enhance biodegradation of hydrocarbons requiring initial monooxygenations. Monooxygenation kinetics follow a multiplicative relationship in which the organic substrates (phenol or DCP) and DO have separate Monod terms, while the biomass’s content of NADH + H+ has a first-order term. The monooxygenase enzyme has different affinities (K values) for phenol and DCP. The biomass’s NADH + H+ content is based on a proportioning of NAD(H) according to the relative rates of NADH + H+ sources and sinks. Biomass synthesis occurs simultaneously through utilization of acetate, phenol, and DCP, but each has its own true yield. The ACCEL model accurately simulates all trends for one-tank and two-tank experiments in which acetate, phenol, and DCP are biodegraded together. In particular, DCP removal is affected most by DOacc and the retention-time ratio, Θacc/Θtotal. Adding an accelerator tank dramatically increases DCP removal, and the best DCP removal occurs for 0.2 〈 DOacc  〈 0.5 mg/l and 0.08 〈 Θacc/Θtotal 〈 0.2. The rates of phenol and DCP utilization follow the multiplicative relationship with a maximum specific rate coefficient proportional to μacc. Finally, μacc increases rapidly for Θacc/Θtotal 〈 0.25, acetate removal in the accelerator fuels the high μacc, and the biomass’s NADH + H+ content increases very dramatically for DOacc 〈 0.25 mg/l.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10532-005-5019-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Beta-decay studies of neutron-rich Sc- Cr nuclei (2005)
    Springer
    The European physical journal 23 (2005), S. 41-48 
    Details
    ISSN: 1434-601X
    Keywords: 27.50.+e 59 ⩽ A ⩽ 89 ; 23.40.-s β decay; double β decay; electron and muon capture ; 21.60.Cs Shell model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The neutron-rich nuclei          2157, 58Sc,          2258-60Ti,          2360-63V,          2462-66Cr have been produced at Ganil via interactions of a 61.8A MeV 76Ge beam with a 58Ni target. Beta-decay studies have been performed using combined β- and γ-ray spectroscopy. Half-lives have been determined and β-decay schemes are proposed for 58Ti, 61V and 62Cr. From these studies, new hints for the existence of β-decaying isomers in 60V and in 62Mn are provided. These results are compared to shell model calculations. The role of the πf7/2- νf5/2 proton-neutron interaction is examined through its influence on the lifetime values.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epja/i2004-10068-x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Spallation neutron spectrum on a massive lead/paraffin target irradiated with 1 GeV protons (2005)
    Springer
    The European physical journal 23 (2005), S. 61-68 
    Details
    ISSN: 1434-601X
    Keywords: 28.41.Kw Radioactive wastes, waste disposal ; 29.30.Kv X- and γ-ray spectroscopy ; 02.70.Uu Applications of Monte Carlo methods ; 07.05.Fb Design of experiments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The gamma-ray spectra emitted by decaying of residual nuclei produced by spallation neutrons in (n, xn), (n, xnyp), (n, p), (n, γ) reactions with activation threshold detectors, i.e. 209Bi, 197Au, 59Co, 115In, 232Th, were measured in the Laboratory of Nuclear Problems (LNP), JINR, Dubna, Russia. Spallation neutrons were generated by bombarding a 20 cm long cylindrical lead target with 8 cm diameter surrounded by a 6 cm thick layer of paraffin moderator with 1 GeV proton beam from the NUCLOTRON accelerator. Reaction rates and a spallation neutron spectrum were measured and compared with CASCADE code calculations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epja/i2004-10031-y
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Emission of unbound 8Be and 12C * (0+2) clusters in compound nucleus reactions (2005)
    Springer
    The European physical journal 23 (2005), S. 19-31 
    Details
    ISSN: 1434-601X
    Keywords: 21.60.Gx Cluster models ; 23.90.+w Other topics in radioactive decay and in-beam spectroscopy ; 25.70.Gh Compound nucleus ; 25.70.Pq Multifragment emission and correlations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We have studied the emission of light unbound clusters, 8Be and 12C * (0+2), in the reactions 18O + 13C →{31} Si →{23} Ne + 8Be and 28Si + 24Mg →{52} Fe →{40} Ca + 12C * (0+2). The γ-ray spectra obtained in coincidence with 8Be and 12C * (0+2) emission have been studied relative to the statistical emission of two or three α-particles. The angular-momentum-to-energy balance of the cluster emission is compared with that of multiple-α emission. The properties of the energy spectra of the binary process and the population of the residual nuclei by cluster emission are discussed. It is observed that cluster emission carries away less excitation energy on average than the sequential emission of the individual components.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epja/i2004-10071-3
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    On kaonic deuterium. Quantum field-theoretic and relativistic covariant approach (2005)
    Springer
    The European physical journal 23 (2005), S. 79-111 
    Details
    ISSN: 1434-601X
    Keywords: 11.10.Ef Lagrangian and Hamiltonian approach ; 11.55.Ds Exact S matrices ; 13.75.Gx Pion-baryon interactions ; 36.10.-k Exotic atoms and molecules (containing mesons, muons, and other unusual particles)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We study kaonic deuterium, the bound K-d state AK d. Within a quantum field-theoretic and relativistic covariant approach we derive the energy level displacement of the ground state of kaonic deuterium in terms of the amplitude of K-d scattering for arbitrary relative momenta. Near threshold our formula reduces to the well-known DGBT formula. The S-wave amplitude of K-d scattering near threshold is defined by the resonances Λ(1405), Σ(1750) and a smooth elastic background, and the inelastic channels K-d → NY and K-d → NYπ, where Y = Σ±,Σ{0} and Λ{0}, where the final-state interactions play an important role. The Ericson-Weise formula for the S-wave scattering length of K-d scattering is derived. The total width of the energy level of the ground state of kaonic deuterium is estimated using the theoretical predictions of the partial widths of the two-body decays AKd → NY and experimental data on the rates of the NY pair production in the reactions K-d → NY. We obtain Γ{1s} = (630±100)eV. For the shift of the energy level of the ground state of kaonic deuterium we predict ε{1s} = (325±60)eV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epja/i2004-10055-3
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    P-wave charmonium decays into baryon and antibaryon pairs in quark pair creation model (2005)
    Springer
    The European physical journal 23 (2005), S. 129-133 
    Details
    ISSN: 1434-601X
    Keywords: 13.25.Gv Decays of J/ψ, ϒ, and other quarkonia ; 12.39.Jh Nonrelativistic quark model ; 14.20.Jn Hyperons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. A simple quark pair creation model is introduced to study exclusive decays of χ{c_J} into baryon-antibaryon pairs. With this simple model, some exclusive decay processes, for example, χ{c0} → B¯ (B = Λ,Σ0,Ξ-) are investigated and their decay widths are evaluated by inclusion of the properties of outgoing baryons, and the results show that the strengthened decay channels χ{c_J} → Λ¯(J = 0, 2) are easily understood by considering only the color singlet contribution of P-wave charmonium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epja/i2004-10069-9
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    The neutron decay retardation spectrometer aSPECT: Electromagnetic design and systematic effects (2005)
    Springer
    The European physical journal 23 (2005), S. 135-146 
    Details
    ISSN: 1434-601X
    Keywords: 23.40.-s Beta decay; double beta decay; electron and muon capture ; 13.30.-a Decays of baryons ; 12.15.Hh Determination of Kobayashi-Maskawa matrix elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The apparatus described here, aSPECT, will be used for a measurement of the neutrino-electron angular correlation coefficient a in the decay of free neutrons. The idea of the aSPECT spectrometer is to measure the integrated proton energy spectrum very accurately using an energy filter by electrostatic retardation and magnetic adiabatic collimation. The main ideas of the spectrometer are presented, followed by an explanation of the adiabatic transmission function. Details of the superconducting coil and of the electrode system are given, as well as a discussion of the most important systematic effects: magnetic field and electrostatic potential inhomogeneities, deviation from adiabatic motion, scattering in the residual gas, background, Doppler effect, edge effect, and detector efficiency. Using this spectrometer, the parameter a is planned to be measured with an absolute experimental uncertainty of δa ≈ 3 . 10-4, from which the axial vector to vector coupling constant ratio λ can be determined with an accuracy of δλ ≈ 0.001.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epja/i2004-10057-1
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Modeling the pion and kaon form factors in the timelike region (2005)
    Springer
    The European physical journal 39 (2005), S. 41-54 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. New, accurate measurements of the pion and kaon electromagnetic form factors are expected in the near future from experiments at electron-positron colliders, using the radiative return method. We construct a model for the timelike pion electromagnetic form factor that is valid also at momentum transfers far above the $\rho$ resonance. The ansatz is based on vector dominance and includes a pattern of radial excitations expected from dual resonance models. The form factor is fitted to the existing data in the timelike region, continued to the spacelike region and compared with the measurements there and with the QCD predictions. Furthermore, the model is extended to the kaon electromagnetic form factor. Using isospin and SU(3)-flavor symmetry relations we extract the isospin-one contribution and predict the kaon weak form factor accessible in semileptonic $\tau$ decays.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02064-3
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Longitudinal $\bar{\Lambda}_0$ polarization in heavy-ion collisions as a probe for QGP formation (2005)
    Springer
    The European physical journal 39 (2005), S. 95-99 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We present an analysis of the longitudinal $\bar{\Lambda}_0$ polarization in ultrarelativistic heavy-ion collisions. The polarization of $\bar{\Lambda}_0$ ’s coming from the decay chain $\bar{\Xi}\rightarrow \bar{\Lambda}_0 + \pi$ exhibits a very well differentiated behavior depending on the production region of the primordial $\bar{\Xi}$ ’s. This effect reflects the different values of the $N_{\bar{\Xi}}/N_{\bar{\Lambda}_0}$ ratio in the QGP region, where nucleon-nucleon interactions take place in a hot and dense environment, and the peripherical region, in which ordinary nucleon-nucleon interactions occur. An increase in the longitudinal $\bar{\Lambda}_0$ polarization signals a strangeness enhancement which is thought of as a property of the QGP phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02073-2
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    The low-lying mass spectrum of the N = 1 SU(2) SUSY Yang-Mills theory with Wilson fermions (2005)
    Springer
    The European physical journal 39 (2005), S. 87-94 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We analyze the low energy spectrum of bound states of the N = 1 SU(2) SUSY Yang-Mills Theory (SYM). This work continues the investigation of the non-perturbative properties of SYM by Monte Carlo simulations in the Wilson discretization with dynamical gluinos. The dynamics of the gluinos is included by the Two-Step Multi-Bosonic Algorithm (TSMB) for dynamical fermions. A new set of configurations has been generated on a $16^3\cdot 32$ lattice at $\beta = 2.3$ and $\kappa = 0.194$ . The analysis also includes sets of configurations previously generated on a smaller ( $12^3\cdot 24$ ) lattice at $\kappa = 0.1925, 0.194$ and 0.1955. Guided by predictions from low energy Lagrangians, we consider spin-1/2, scalar and pseudoscalar particles. The spectrum of SYM is a challenging subject of investigation because of the extremely noisy correlators. In particular, meson-like correlators contain disconnected contributions. The larger time-extension of the $16^3\cdot 32$ lattice allows to observe two-state signals in the effective mass. Finite-volume effects are monitored by comparing results from the two lattice sizes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02081-2
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Twisted mass quarks and the phase structure of lattice QCD (2005)
    Springer
    The European physical journal 39 (2005), S. 421-433 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The phase structure of zero temperature twisted mass lattice QCD is investigated. We find strong metastabilities in the plaquette observable in correspondence of which the untwisted quark mass assumes positive or negative values. We provide interpretations of this phenomenon in terms of chiral symmetry breaking and the effective potential model of Sharpe and Singleton.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02078-9
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Jet production in pA and AA collisions in the perturbative QCD pomeron model (2005)
    Springer
    The European physical journal 39 (2005), S. 451-464 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Inclusive cross-sections for gluon jet production are studied numerically in the perturbative QCD pomeron model for pA and central AA collisions at high energies. Two forms for the inclusive cross-sections, with and without emission from the triple pomeron vertex, are compared. The difference was found to reduce to a numerical factor $\sim 0.7\div 0.8$ for momenta below the saturation momentum Q s. Above Q s no difference was found at all. For pA collisions the gluon spectrum was found to be $\sim A^{0.7}$ at momenta k below Q s and $\sim A^{0.9}$ above it. For central AA collisions it was found to be $\sim A$ at momenta k below Q s and $\sim A^{1.1}$ above it. At large k the spectrum goes like $1/k^{2.7\div 3.3}$ , flattening with energy. The multiplicities turned out to be proportional to A 0.7 for pA collisions and A for central AA collisions with a good precision. In the latter case they are becoming more peaked at the center with the growth of energy. Their absolute values are high and grow rapidly with energy in accordance with the high value of the BFKL intercept.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02098-5
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Improved phase space treatment of massive multi-particle final states (2005)
    Springer
    The European physical journal 39 (2005), S. 439-450 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. In this paper the revised Kajantie-Byckling approach and improved phase space sampling techniques for the massive multi-particle final states are presented. The application of the developed procedures to the processes representative for LHC physics indicates the possibility of a substantial simplification of multi-particle phase space sampling while retaining a respectable weight variance reduction and unweighing efficiencies in the event generation process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02105-y
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Observing higher-dimensional black holes at the LHC (2005)
    Springer
    The European physical journal 39 (2005), S. 503-509 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. A new approach to spacetime proposing the existence of n compactified large extra dimensions predicts the creation of higher-dimensional black holes at the LHC of CERN. In case they form, signatures of such black holes at accelerators would be quite significant and black hole decay products would carry valuable information for particle physics and cosmology. In this study we first make a short theoretical introduction, then present the results of an analysis made on a Monte Carlo simulation modeling black hole production and decay at the LHC. This analysis includes the examination of the lepton case in black hole to Higgs decay channels, reconstruction of the black hole masses, a calculation of the Hawking temperature and a determination of the radiated jets/leptons multiplicity ratio.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02111-1
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Orbifold compactification and solutions of M-theory from Milne spaces (2005)
    Springer
    The European physical journal 39 (2005), S. 519-524 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. In this paper, we consider solutions and spectral functions of M-theory from Milne spaces with extra free dimensions. Conformal deformations to the metric associated with real hyperbolic space forms are derived. For the three-dimensional case, the orbifold identifications ${\mathrm{SL}}(2,{\mathbb{Z}} + {\mathrm{i}}{\mathbb{Z}})/\{\pm {\mathrm{Id}}\}$ , where Id is the identity matrix, is analyzed in detail. The spectrum of an eleven-dimensional field theory can be obtained with the help of the theory of harmonic functions in the fundamental domain of this group and it is associated with the cusp forms and the Eisenstein series. The supersymmetry surviving for supergravity solutions involving real hyperbolic space factors is briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02117-1
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Isospin constraints from/on $B \to \pi\pi$ (2005)
    Springer
    The European physical journal 39 (2005), S. 397-409 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The Standard Model constraints on $\alpha$ which can be derived from the $B\rightarrow\pi\pi$ decays are revisited in some depth. As experimental inputs, the $B^0\rightarrow\pi^ + \pi^-$ , $B^ + \rightarrow\pi^ + \pi^0$ decays complemented by the $B^0\rightarrow\pi^0\pi^0$ decays, the CP parameters $S_{\pi\pi}$ and $C_{\pi\pi}$ , and/or the value of $\alpha$ as determined by the global CKM fit are used. The constraints discussed here are model independent in the sense that they rely only on Isospin symmetry, following the Gronau-London proposal. A new bound on $\mathcal{B}^{00}$ and the function $C_{00}(\mathcal{B}^{00})$ are introduced. While another bound applied to BABAR results is shown to imply that $\cos(2\alpha_{\rm eff})$ is negative. The Grossman-Quinn bound is rediscussed. A close form expression is given for $\alpha$ as a function of the measurements. Various scenarios for the future of the isospin analysis are explored. To probe the Standard Model the $(\mathcal{B}^{00},C_{00})$ plane is introduced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02119-y
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Anomalous suppression of $\pi^0$ production at large transverse momentum in Au + Au and d + Au collisions at $\sqrt{{\bf s}_{\bf NN}} = 200$ GeV (2005)
    Springer
    The European physical journal 40 (2005), S. 129-135 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We propose a model of the suppression of large p T pions in heavy ion collisions based on the interaction of the large p T pion with the dense medium created in the collision. The model is practically the same as the one previously introduced to describe $J/\psi$ suppression. Both the p T and the centrality dependence of the data are reproduced. In deuteron-gold collisions, the effect of the final state interaction with the dense medium turns out to be negligibly small. Here the main features of the data are also reproduced both at mid and at forward rapidities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02097-6
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Determination of A FB b at the Z pole using inclusive charge reconstruction and lifetime tagging (2005)
    Springer
    The European physical journal 40 (2005), S. 1-25 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. A novel high precision method measures the b-quark forward-backward asymmetry at the Z pole on a sample of 3,560,890 hadronic events collected with the DELPHI detector in 1992 to 2000. An enhanced impact parameter tag provides a high purity b sample. For event hemispheres with a reconstructed secondary vertex the charge of the corresponding quark or anti-quark is determined using a neural network which combines in an optimal way the full available charge information from the vertex charge, the jet charge and from identified leptons and hadrons. The probability of correctly identifying b-quarks and anti-quarks is measured on the data themselves comparing the rates of double hemisphere tagged like-sign and unlike-sign events. The b-quark forward-backward asymmetry is determined from the differential asymmetry, taking small corrections due to hemisphere correlations and background contributions into account. The results for different centre-of-mass energies are: $$ A_{\mathrm{FB}}^{{\mathrm{b}}} (89.449 \mathrm{GeV}) = 0.0637 \pm 0.0143(\mbox{stat.}) \pm 0.0017(\mbox{syst.})$$ $$A_{\mathrm{FB}}^{{\mathrm{b}}} (91.231 \mathrm{GeV}) = 0.0958 \pm 0.0032(\mbox{stat.}) \pm 0.0014(\mbox{syst.})$$ $$A_{\mathrm{FB}}^{{\mathrm{b}}} (92.990 \mathrm{GeV}) = 0.1041 \pm 0.0115(\mbox{stat.}) \pm 0.0024(\mbox{syst.})$$ . Combining these results yields the b-quark pole asymmetry $$ A_{\mathrm{FB}}^{{\mathrm{b, 0}}} = 0.0972 \pm 0.0030(\mbox{stat.}) \pm 0.0014(\mbox{syst.}) . $$
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02104-0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Effective action and Hawking flux from covariant perturbation theory (2005)
    Springer
    The European physical journal 40 (2005), S. 275-286 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The computation of the radiation flux related to the Hawking temperature of a Schwarzschild black hole or another geometric background is still well-known to be fraught with a number of delicate problems. In spherical reduction, as shown by one of the present authors (Kummer) with Vassilevich, the correct black body radiation follows when two “basic components” (conformal anomaly and a “dilaton” anomaly) are used as input in the integrated energy-momentum conservation equation. The main new element in the present work is the use of a quite different method, the covariant perturbation theory of Barvinsky and Vilkovisky, to establish directly the full effective action which determines these basic components. In the derivation of Kummer and Vassilevich the computation of the dilaton anomaly implied one potentially doubtful intermediate step which can be avoided here. Moreover, the present approach also is sensitive to IR (renormalization) effects. We realize that the effective action naturally leads to expectation values in the Boulware vacuum which, making use of the conservation equation, suffice for the computation of the Hawking flux in other quantum states, in particular for the relevant Unruh state. Thus, a rather comprehensive discussion of the effects of (UV and IR) renormalization upon radiation flux and energy density is possible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02129-9
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Correlator of heavy-quark currents at small q 2 in the large- $\beta_0$ limit (2005)
    Springer
    The European physical journal 40 (2005), S. 157-164 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The correlator of vector heavy-quark currents at small q 2 is considered in the large- $\beta_0$ limit. The leading IR renormalon ambiguity of the sum of the perturbative series is canceled by the UV renormalon ambiguity of the gluon condensate. The asymptotic behavior of the perturbative series is obtained in a model-independent way, up to a single unknown normalization factor. Gluon-virtuality distribution functions for the perturbative correction are calculated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02124-2
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    The difference between n-dimensional regularization and n-dimensional reduction in QCD (2005)
    Springer
    The European physical journal 40 (2005), S. 199-203 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We discuss the difference between n-dimensional regularization and n-dimensional reduction for processes in QCD which have an additional mass scale. Examples are heavy flavor production in hadron-hadron collisions or on-shell photon-hadron collisions where the scale is represented by the mass m. Another example is electroproduction of heavy flavors where we have two mass scales given by m and the virtuality of the photon $\smash[b]{Q = \sqrt{-q^2}}$ . Finally we study the Drell-Yan process where the additional scale is represented by the virtuality $\smash[t]{Q = \sqrt{q^2}}$ of the vector boson ( $\gamma^*, W, Z$ ). The difference between the two schemes is not accounted for by the usual oversubtractions. There are extra counter terms which multiply the mass scale dependent parts of the Born cross sections. In the case of the Drell-Yan process it turns out that the off-shell mass regularization agrees with n-dimensional regularization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02144-x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Measurements of the charge asymmetry of the Dalitz plot parameters for $K^{\pm}\to\pi^{\pm}\pi^0\pi^0$ decays (2005)
    Springer
    The European physical journal 40 (2005), S. 343-347 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The charge asymmetry of the g, h, and k Dalitz plot parameters for ${K^{\pm}\rightarrow \pi^{\pm} \pi^{0} \pi^{0}}$ decays has been measured with 35 GeV/c hadron beams at the 70 GeV IHEP accelerator. The g, h, and k values obtained appear to be identical for $K^{\pm}$ decays within the errors quoted. In particular, the charge asymmetry A g = (g + – g -)/(g + + g -) of the slope g is equal to ${(0.2 \pm 1.9)\cdot 10^{-3}}$ .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02138-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Measurement of $F_2^{c\bar{c}}$ and $F_2^{b\bar{b}}$ at high Q 2 using the H1 vertex detector at HERA (2005)
    Springer
    The European physical journal 40 (2005), S. 349-359 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Measurements are presented of inclusive charm and beauty cross sections in e + p collisions at HERA for values of photon virtuality Q 2 〉 150 GeV2 and of inelasticity 0.1 〈 y 〈 0.7. The charm and beauty fractions are determined using a method based on the impact parameter, in the transverse plane, of tracks to the primary vertex, as measured by the H1 vertex detector. The data are divided into four regions in Q 2 and Bjorken x, and values for the structure functions $F_2^{c\bar{c}}$ and $F_2^{b\bar{b}}$ are obtained. The results are found to be compatible with the predictions of perturbative quantum chromodynamics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02154-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    H/A Higgs mixing in CP-noninvariant supersymmetric theories (2005)
    Springer
    The European physical journal 40 (2005), S. 555-564 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. For large masses, the two heavy neutral Higgs bosons are nearly degenerate in many 2-Higgs doublet models, and particularly in supersymmetric models. In such a scenario the mixing between the states can be very large if the theory is CP-noninvariant. We analyze the formalism describing this configuration, and we point to some interesting experimental consequences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02145-9
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Study of the neutron quantum states in the gravity field (2005)
    Springer
    The European physical journal 40 (2005), S. 479-491 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We have studied neutron quantum states in the potential well formed by the earth’s gravitational field and a horizontal mirror. The estimated characteristic sizes of the neutron wave functions in the two lowest quantum states correspond to expectations with an experimental accuracy. A position-sensitive neutron detector with an extra-high spatial resolution of $\sim 2 \mathrm{\mu} $ m was developed and tested for this particular experiment, to be used to measure the spatial density distribution in a standing neutron wave above a mirror for a set of some of the lowest quantum states. The present experiment can be used to set an upper limit for an additional short-range fundamental force. We studied methodological uncertainties as well as the feasibility of improving further the accuracy of this experiment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02135-y
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Optimal observables and phase-space ambiguities (2005)
    Springer
    The European physical journal 40 (2005), S. 497-503 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Optimal observables are known to lead to minimal statistical errors on parameters for a given normalised event distribution of a physics reaction. Thereby all statistical correlations are taken into account. Therefore, on the one hand they are a useful tool to extract values on a set of parameters from measured data. On the other hand one can calculate the minimal constraints on these parameters achievable by any data-analysis method for the specific reaction. In case the final states can be reconstructed without ambiguities optimal observables have a particularly simple form. We give explicit formulae for the optimal observables for generic reactions in case of ambiguities in the reconstruction of the final state and for general parameterisation of the final-state phase space.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02153-9
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Universality of the transverse momentum distributions in the framework of percolation of strings (2005)
    Springer
    The European physical journal 40 (2005), S. 229-241 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. In the framework of percolation of color sources, the transverse momentum distribution in heavy ion and p + p collisions at all centralities and energies are shown to follow a universal behavior. The width of the distribution depends on the fluctuations of the number of color sources per cluster. At low densities, there are only independent single color sources, no fluctuations occur and the distribution is described by a single exponential. At very high densities, only one cluster of many color sources appears and therefore there are not fluctuations either and the hardness of the distribution is suppressed. The Cronin effect in this framework is due to a maximum of the fluctuations which decreases as the density increases. We obtain a good agreement with experimental data including the low p T behavior and the spectra for different particles. We show that the transverse momentum and multiplicity distributions are related to each other in a defined way. This point is satisfied by the experimental data on p + p collisions at different energies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02127-y
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    New gauge bosons from the littlest Higgs modeland the process $e^{ + }e^{-}\rightarrow t\bar{t}$ (2005)
    Springer
    The European physical journal 40 (2005), S. 251-258 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. In the context of the littlest Higgs (LH) model, we study the process $e^{ + }e^{-}\rightarrow t\bar{t}$ . We find that the new gauge bosons Z H and B H can produce significant correction effects on this process, which can be further enhanced by suitably polarized beams. In most of the parameter space preferred by the electroweak precision data, the absolute value of the relative correction parameter $R_{B_{H}}$ is larger than 5 %. As long as $1 {\mathrm {TeV}} \leq M_{Z_{H}}\leq 1.5 {\mathrm {TeV}} $ and $0.3\leq c\leq 0.5,$ the absolute value of the relative correction parameter $R_{Z_{H}}$ is larger than $5\%$ . With reasonable values of the parameters of the LH model, the possible signals of the new gauge bosons B H and Z H can be detected via the process $e^{ + }e^{-}\rightarrow t\bar{t}$ in the future LC experiments with the CM energy $\sqrt{S} = 800 {\mathrm {GeV}} $ . B H exchange and Z H exchange can generate significantly corrections to the forward-backward asymmetry $A_{\mathrm {{FB}}}(t\bar{t})$ only in a small part of the parameter space.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02131-3
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Exclusive semileptonic rare decays $B \to K^{(*)} l^ + l^-$ in a SUSY SO(10) GUT (2005)
    Springer
    The European physical journal 40 (2005), S. 565-577 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. In the SUSY SO(10) GUT context, we study the exclusive processes $B \to K^{(*)} l^ + l^-(l = \mu,\tau)$ . Using the Wilson coefficients of the relevant operators including the new operators $\smash{Q_{1,2}^{(\prime)}}$ which are induced by neutral Higgs boson (NHB) penguins, we evaluate some possible observables associated with these processes like the invariant mass spectrum (IMS), lepton pair forward-backward asymmetry (FBA), lepton polarization asymmetries etc. In this model the contributions from Wilson coefficients $C_{Q_{1,2}}^\prime$ , among new contributions, are dominant. Our results show that the NHB effects are sensitive to the FBA, $\mathrm {d}L/\mathrm {d}\hat{s}$ , and $\mathrm {d}T/\mathrm {d}\hat{s}$ of $B \to K^{(*)} \tau^ + \tau^-$ decay, which are expected to be measured in B factories, the deviation of $\mathrm {d}T/\mathrm {d}\hat{s}$ in $B \to K \mu^ + \mu^-$ can reach 0.1 from SM, which could be seen in B factories, and the average of the normal polarization $\mathrm {d}N/\mathrm {d}\hat{s}$ can reach several percent for $B \to K \mu^ + \mu^-$ and it is 0.05 or so for $B\to K \tau^ + \tau^-$ , which could be measured in the future super B factories and provide useful information to probe new physics and discriminate different models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02132-2
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Corrections to quark asymmetries at LEP (2005)
    Springer
    The European physical journal 40 (2005), S. 493-496 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The most precise measurement of the weak mixing angle $\sin^2 \theta_{\mathrm{eff}}^l$ at LEP is from the forward-backward asymmetry $e^ + e^- \rightarrow b \overline{b}$ at the Z-pole. In this note the QED and electroweak radiative corrections to obtain the pole asymmetry from the measured asymmetry for b- and c-quarks have been calculated using ZFITTER, which has been amended to allow a consistent treatment of partial two-loop corrections for the b-quark final asymmetries. A total correction of $\delta A_{\mathrm{FB}}^{{b}} = 0.0019 \pm 0.0002$ and $\delta A_{\mathrm{FB}}^{{c}} = 0.0064 \pm 0.0001$ has been found, where the remaining theoretical uncertainty is much too small to explain the apparent discrepancy between $\sin^2 \theta_{\mathrm{eff}}^l$ obtained from A FB b and from the left-right asymmetry at SLD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02164-6
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Probing the perturbative NLO parton evolution in the small-x region (2005)
    Springer
    The European physical journal 40 (2005), S. 515-517 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. A dedicated test of the perturbative QCD NLO parton evolution in the very small-x region is performed. We find a good agreement with recent precision HERA data for F 2 p(x,Q 2), as well as with the present determination of the curvature of F 2 p. Characteristically, perturbative QCD evolutions result in a positive curvature which increases as x decreases. Future precision measurements in the very small x-region, x 〈 10-4, could provide a sensitive test of the range of validity of perturbative QCD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02167-3
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    The QCD pomeron in ultraperipheral heavy ion collisions: IV. Photonuclear production of vector mesons (2005)
    Springer
    The European physical journal 40 (2005), S. 519-529 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The photonuclear production of vector mesons in ultraperipheral heavy-ion collisions is investigated within the QCD color dipole picture, with particular emphasis on the saturation model. The integrated cross section and the rapidity distribution for the $AA \rightarrow V AA$ ( $V = \rho, \omega, \phi, J/\Psi$ ) process are computed and theoretical estimates for scattering on both light and heavy nuclei are given for the energies of RHIC and LHC. A comparison with the recent STAR data on coherent production of $\rho$ mesons is also presented. Furthermore, we calculate the photoproduction of vector mesons in proton-proton collisions at RHIC, Tevatron and LHC energies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02175-3
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Pomeron vertices in perturbative QCD in diffractive scattering (2005)
    Springer
    The European physical journal 40 (2005), S. 419-433 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We analyze the momentum space triple pomeron vertex in perturbative QCD. In addition to the standard form of this vertex which is used in the context of total cross sections at high energies and in the QCD reggeon field theory, there exists an alternative form which has to be used in the study of high-mass diffraction. We review and analyze the relation between these two versions. We discuss some implications for the BK equation. In the second part of our paper we extend this analysis to the pomeron-odderon-odderon vertex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02152-x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Phase diagram in the quantum XY model with long-range interactions (2005)
    Springer
    The European physical journal 43 (2005), S. 93-96 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We study the d-dimensional quantum XY model with ferromagnetic long-range interaction decaying as r-p in terms of boson operators, by employing the coherent state path integral approach. We have obtained a finite critical temperature as a function of the dimension (d) for d〈p〈2d. For p〉2d the system becomes disordered at all temperatures. For the particular values p=3/2 and d=1 our theoretical calculations are comparable to those from Monte Carlo simulations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2005-00031-9
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Magnetic structure of the spin-1/2 layer compound NaNiO2 (2005)
    Springer
    The European physical journal 43 (2005), S. 159-162 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We have carried out high resolution neutron powder diffraction experiments aiming at a determination of the magnetic structure of the S=1/2 layer compound NaNiO2. The magnetic moments are ferromagnetically aligned in the NiO2 layers and antiparallel between layers. The direction of the magnetic moment has a small component along the a-direction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2005-00038-2
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Fermionic Ising glasses in magnetic transverse field with BCS pairing interaction (2005)
    Springer
    The European physical journal 43 (2005), S. 187-193 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We study a fermionic infinited-ranged Ising spin glass with a real space BCS interaction in the presence of an applied transverse field. The problem is formulated in the integral functional formalism where the SU(2) spins are given in terms of bilinear combinations of Grassmann fields. The problem is solved within static approximation and the replica symmetry ansatz combined with previous approaches used to study the critical behavior of the quantum Ising spin glass in a transverse field and the spin glass Heisenberg model with BCS pairing. Our results show that the transverse field has strong effect in the phase boundary of the spin glass phase and the PAIR phase in which there is a long range order corresponding to formations of pairs. The location of the tricritical point in the PAIR phase transition line is also affected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2005-00041-7
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Crossover component in non critical dissipative sandpile models (2005)
    Springer
    The European physical journal 43 (2005), S. 213-220 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The effect of bulk dissipation on non critical sandpile models is studied using both multifractal and finite size scaling analyses. We show numerically that the local limited (LL) model exhibits a crossover from multifractal to self-similar behavior as the control parameters hext and epsilon turn towards their critical values, i.e. hext →0+ and epsilon→epsilonc. The critical exponents are not universal and exhibit a continuous variation with epsilon. On the other hand, the finite size effects for the local unlimited (LU), non local limited (NLL), and non local unlimited (NLU) models are well described by the multifractal analysis for all values of dissipation rate epsilon. The space-time avalanche structure is studied in order to give a deeper understanding of the finite size effects and the origin of the crossover behavior. This result is confirmed by the calculation of the susceptibility.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2005-00044-4
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Nonextensive thermostatistic properties of a q-generalized Fermi system (2005)
    Springer
    The European physical journal 43 (2005), S. 271-277 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Based on the generalized statistic distribution derived from the Tsallis’ entropy that has been successfully used in complex systems with long-range interactions and/or long-duration memory, the thermostatistic properties of a q-generalized Fermi system are studied. The total number of particles, internal energy, and heat capacity at constant volume are calculated for two different cases of q≤1 and q≥1, respectively, where q is an important parameter to evaluate the nonextensivity of the system. The thermostatistic characteristics of the system are discussed in detail. It is found from the results obtained here that the Fermi energy of such a system is independent of the parameter q and is equal to that of an original ideal Fermi system when q≤1, while other thermostatistic properties of the system depend closely on the parameter q. For example, when q〈1, the chemical potential of the system in certain region of temperature may be larger than the Fermi energy; when q〉1, some thermodynamic parameters of the system at low temperatures must be cut off.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2005-00048-0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Photon events with missing energy in e + e- collisions at $\sqrt{s} = {}$ 130 to 209 GeV (2005)
    Springer
    The European physical journal 38 (2005), S. 395-411 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The production of single- and multi-photon events has been studied in the reaction $e^ + e^-\rightarrow\gamma(\gamma) + invisible \quad particles$ . The data collected with the DELPHI detector during the years 1999 and 2000 at centre-of-mass energies between 191 GeV and 209 GeV was combined with earlier data to search for phenomena beyond the Standard Model. The measured number of light neutrino families was consistent with three and the absence of an excess of events beyond that predicted by the Standard Model processes was used to set limits on new physics. Both model-independent searches and searches for new processes predicted by supersymmetric and extra-dimensional models have been made. Limits on new non-standard model interactions between neutrinos and electrons were also determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02051-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    A systematic study of neutrino mixing and CP-violationfrom lepton mass matrices with six texture zeros (2005)
    Springer
    The European physical journal 38 (2005), S. 495-510 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We present a systematic study of 400 combinations of the charged lepton and neutrino mass matrices with six vanishing entries or texture zeros. Only 24 of them, which can be classified into a few distinct categories, are found to be compatible with current neutrino oscillation data at the $3\sigma$ level. A peculiar feature of the lepton mass matrices in each category is that they have the same phenomenological consequences. Taking account of a simple seesaw scenario for six parallel patterns of the charged lepton and Dirac neutrino mass matrices with six zeros, we show that it is possible to fit the experimental data at or below the $2\sigma$ level. In particular, the maximal atmospheric neutrino mixing can be reconciled with a strong neutrino mass hierarchy in the seesaw case. Numerical predictions are also obtained for the neutrino mass spectrum, flavor mixing angles, CP-violating phases and effective masses of the tritium beta decay and the neutrinoless double beta decay.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02065-2
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Leading-particle suppression in high energy nucleus-nucleus collisions (2005)
    Springer
    The European physical journal 38 (2005), S. 461-474 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Parton energy loss effects in heavy-ion collisions are studied with the Monte Carlo program PQM (Parton Quenching Model) constructed using the BDMPS quenching weights and a realistic collision geometry. The merit of the approach is that it contains only one free parameter that is tuned to the high-p t nuclear modification factor measured in central Au-Au collisions at $\sqrt{s_{\rm NN}} = 200$ GeV. Once tuned, the model is consistently applied to all the high-p t observables at 200 GeV: the centrality evolution of the nuclear modification factor, the suppression of the away-side jet-like correlations, and the azimuthal anisotropies for these observables. Predictions for the leading-particle suppression at nucleon-nucleon centre-of-mass energies of 62.4 and 5500 GeV are presented. The limits of the eikonal approximation in the BDMPS approach, when applied to finite-energy partons, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02077-x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    B decays into light scalar particles and glueball (2005)
    Springer
    The European physical journal 39 (2005), S. 71-86 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The recent observations of f 0(980) in charmless B decays motivate further studies of scalar particle and glueball production in these processes. Amplitudes for charmless two-body B decays involving the members of the scalar nonet are presented based on the symmetries of the dominant penguin contribution. Different scenarios for the lightest scalar nonet are investigated in view of the presently available data. We describe the evidence from B decays for f 0(1500) with a flavor octet like mixing and the hints towards the members of the $q\bar{q}$ nonet of lowest mass. There is further support for the hypothesis of a broad 0 + + glueball acting as coherent background especially in $B\to K\overline K K$ . The estimated B decay rates into gluonic mesons represent a sizable fraction of the theoretically derived decay rate for ${b\to sg}$ .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02071-4
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Coherent production of pairs of parabosons of order 2 (2005)
    Springer
    The European physical journal 39 (2005), S. 109-121 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. A parameter-free statistical model is used to study multiplicity signatures for coherent production of charged pairs of parabosons of order p = 2 in comparison with those arising in the case of ordinary bosons, p = 1. Two non-negative real parameters arise because “ab” and “ba” are fundamentally distinct pair operators of charge “ + 1”, A-quanta and charge “-1”, B-quanta parabosons. In 3D plots of ${P_{m}}(q)\equiv$ “the probability of m paraboson charged pairs + q positive parabosons” versus $\langle n\rangle $ and $\langle n^2\rangle $ , the p = 1 curve is found to lie on the relatively narrow 2D p = 2 surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02067-0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    On the boundary conditions as Dirac constraints (2005)
    Springer
    The European physical journal 39 (2005), S. 123-127 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. In this paper, the canonical quantization of singular Lagrangian defined in a finite volume is discussed by studying a 1 + 1 dimensional free Schrödinger field. We take the boundary conditions (BCs) as Dirac constraints, and show that those BCs as well as the intrinsic constraints (which are introduced by the singularities of Lagrangian) form the second class constraints. The quantization is performed canonically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02079-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Concerning the Landau pole in 3-3-1 models (2005)
    Springer
    The European physical journal 39 (2005), S. 101-107 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Some 3-3-1 models predict the existence of a non-perturbative regime at the TeV scale. We study in these models and their supersymmetric extensions, the energy at which the non-perturbative limit and a Landau-like pole arise. An order of magnitude for the mass of the extra neutral vector boson, $Z^\prime$ , present in these models is also obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02083-0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Quark-meson SU(3) model in a Tamm-Dancoff inspired approximation (2005)
    Springer
    The European physical journal 38 (2005), S. 483-494 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The non-linear chiral quark-meson U(3) x U(3) model is solved using the Tamm-Dancoff inspired approximation which is described in an earlier paper [Phys. Rev. D 58, 034003 (1998)]. The resulting system of 15 coupled non-linear differential equations self-consistently determines all quark-meson coupling constants. Also the obtained solutions for quark and meson fields are stable and physically acceptable. As the zeroth approximation of a more refined structure they were used to calculate SU(3) baryon octet magnetic moments and axial coupling constants with baryon state vectors containing valence quarks only, at this primordial level. The results are very promising, so possibilities to pursuit more sophistication and improved physical input is indicated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02062-5
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Diffractive $\gamma \gamma$ production at hadron colliders (2005)
    Springer
    The European physical journal 38 (2005), S. 475-482 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We compute the cross section for exclusive double-diffractive $\gamma \gamma$ production at the Tevatron, $p{\bar{p}} \to p + \gamma \gamma + {\bar{p}}$ , and the LHC. We evaluate both the gg and $q\bar{q}\;\; t$ -channel exchange contributions to the process. The observation of exclusive $\gamma \gamma$ production at the Tevatron will provide a check on the model predictions and offer an opportunity to confirm the expectations for exclusive double-diffractive Higgs production at the LHC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02059-0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Zero-curvature formalism of supersymmetric principal chiral model (2005)
    Springer
    The European physical journal 38 (2005), S. 521-526 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We investigate the one-parameter family of transformations on superfields of the super principal chiral model and obtain different zero-curvature representations of the model. The parametric transformation is related to the super Riccati equations and an infinite set of local and non-local conservation laws is derived. A Lax representation of the model is presented which gives rise to a superspace monodromy operator.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02066-1
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Measurement of triple gauge boson couplings at an $e\gamma$ -collider (2005)
    Springer
    The European physical journal 38 (2005), S. 427-436 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. If no light Higgs boson exists, the interaction among the gauge bosons becomes strong at high energies ( $\sim 1 {\rm TeV}$ ). The effects of strong electroweak symmetry breaking (SEWSB) could manifest themselves indirectly as anomalous couplings before they give rise to new physical states like resonances. Here a study of the measurement of trilinear gauge couplings is presented looking at the hadronic decay channel of the W boson at an $e\gamma$ -collider. A sensitivity in the range of 10-3 to 10-4 can be reached depending on the coupling under consideration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02091-0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Casimir effect for gauge fields in spaces with negative constant curvature (2005)
    Springer
    The European physical journal 39 (2005), S. 249-252 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We consider gauge theories based on abelian p-forms on real compact hyperbolic spaces. Using the zeta-function regularization method and the trace tensor kernel formula, we determine explicitly an expression for the vacuum energy (Casimir energy) corresponding to skew-symmetric tensor fields. It is shown that the topological component of the Casimir energy for co-exact forms on even-dimensional spaces, associated with the trivial character, is always negative. We infer on the possible cosmological consequences of this result.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02080-3
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Non-Abelian color dielectric - towards the effective model of the low energy QCD (2005)
    Springer
    The European physical journal 39 (2005), S. 185-193 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Lattice motivated triplet color scalar field theory is analyzed. We consider non-minimal as well as covariant derivative coupling with SU(2) gauge fields. Field configurations generated by external electric sources are presented. Moreover non-Abelian magnetic monopoles are found. Dependence on the spatial coordinates in the obtained solutions is identical as in the usual Abelian case. We show also that after a decomposition of the fields a modified Faddeev-Niemi action can be obtained. It contains explicit O(3) symmetry breaking term parameterized by the condensate of an isoscalar field. Due to that Goldstone bosons observed in the original Faddeev-Niemi model are removed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02087-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Comments on spin operators and spin-polarization states of 2 + 1 fermions (2005)
    Springer
    The European physical journal 39 (2005), S. 245-248 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. In this brief article we discuss spin-polarization operators and spin-polarization states of 2 + 1 massive Dirac fermions and find a convenient representation by the help of 4-spinors for their description. We stress that in particular the use of such a representation allows us to introduce the conserved covariant spin operator in the 2 + 1 field theory. Another advantage of this representation is related to the pseudoclassical limit of the theory. Indeed, quantization of the pseudoclassical model of a spinning particle in 2 + 1 dimensions leads to the 4-spinor representation as the adequate realization of the operator algebra, where the corresponding operator of a first-class constraint, which cannot be gauged out by imposing the gauge condition, is just the covariant operator previously introduced in the quantum theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02026-9
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Hidden local symmetry and chiral effective theory for vector and axial-vector mesons (2005)
    Springer
    The European physical journal 39 (2005), S. 201-208 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. In this paper, we present the full Lagrangian of mesons (pseudoscalars, vectors and axial-vectors) to O(p 4) by using the explicit global chiral symmetry and hidden local symmetry in the chiral limit. In this approach, we see that there are many other terms besides the usual eleven terms given in the literature from a hidden local symmetry approach. In particular, there are some terms in our full results which are important for understanding the vector meson dominance and $\pi$ - $\pi$ scattering and providing consistent predictions on the decay rates of $a_1\rightarrow\gamma\pi$ and $a_1\rightarrow\rho\pi$ as well as for constructing a consistent effective chiral Lagrangian with chiral perturbation theory. It is likely that the structures of the effective chiral Lagrangian for O(p 4) given in the literature by using hidden local symmetry are incomplete and consequently the resulting couplings are not reliable. We examine the issue that the more general effective chiral Lagrangian given in the present paper can provide more consistent predictions for the low energy phenomenology of the $\rho$ -a 1 system and result in more consistent descriptions on the low energy behavior of light flavor mesons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02076-y
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Inelastic $J/\psi$ and $\Upsilon$ hadroproduction (2005)
    Springer
    The European physical journal 39 (2005), S. 163-171 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We consider the prompt hadroproduction of $J/\psi, \psi'$ and the $\Upsilon (1S,2S,3S)$ states caused by the fusion of a symmetric colour-octet state, (gg)8s , and an additional gluon. The cross sections are calculated in leading-order perturbative QCD. We find a considerable enhancement in comparison with previous perturbative QCD predictions. Indeed, the resulting cross sections are found to be consistent with the values measured at the Tevatron and RHIC, without the need to invoke non-perturbative ‘colour-octet’ type of contributions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02090-1
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Exclusive decuplet-baryon pair production in two-photon collisions (2005)
    Springer
    The European physical journal 39 (2005), S. 173-178 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. This work extends our previous studies of two-photon annihilation into baryon-antibaryon pairs from spin-1/2 octet to spin-3/2 decuplet baryons. Our approach is based on perturbative QCD and treats baryons as quark-diquark systems. Using the same model parameters as in our previous work, supplemented by QCD sum-rule results for decuplet baryon wave functions, we are able to give absolute predictions for decuplet baryon cross sections without introducing new parameters. We find that the $\Delta^{ + + }$ cross section is of the same order of magnitude as the proton cross section, well within experimental bounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02092-y
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Energy dependence of gap survival probability and antishadowing (2005)
    Springer
    The European physical journal 39 (2005), S. 435-438 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We discuss the energy dependence of the gap survival probability which follows from the rational form of the amplitude unitarization. In contrast to the eikonal form of unitarization which leads to a decreasing energy dependence of the gap survival probability, we predict a non-monotonous form for this dependence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02102-2
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Non-perturbative pion matrix element of a twist-2 operator from the lattice (2005)
    Springer
    The European physical journal 40 (2005), S. 69-80 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We give a continuum limit value of the lowest moment of a twist-2 operator in pion states from non-perturbative lattice calculations. We find that the non-perturbatively obtained renormalization group invariant matrix element is $\langle x\rangle_{\mathrm{RGI}} = 0.179(11)$ , which corresponds to $\langle x \rangle^{\overline{\mathrm{MS}}}(2\mathrm{ GeV}) = 0.246(15)$ . In obtaining the renormalization group invariant matrix element, we have controlled important systematic errors that appear in typical lattice simulations, such as non-perturbative renormalization, finite size effects and effects of a non-vanishing lattice spacing. The crucial limitation of our calculation is the use of the quenched approximation. Another question that remains not fully clarified is the chiral extrapolation of the numerical data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02121-5
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Radiative K e3 decays revisited (2005)
    Springer
    The European physical journal 40 (2005), S. 205-227 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Motivated by recent experimental results and ongoing measurements, we review the chiral perturbation theory prediction for $K_{\mathrm {L}}\to\pi^{\mp} e^{\pm} \nu_e\gamma$ decays. Special emphasis is given to the stability of the inner bremsstrahlung-dominated relative branching ratio versus the K e3 form factors, and on the separation of the structure-dependent amplitude in differential distributions over the phase space. For the structure-dependent terms, an assessment of the order p 6 corrections is given, in particular, a full next-to-leading order calculation of the axial component is performed. The experimental analysis of the photon energy spectrum is discussed, and other potentially useful distributions are introduced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02123-3
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Extension of the Buchalla-Safir bound (2005)
    Springer
    The European physical journal 40 (2005), S. 187-191 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. I provide a simple derivation of the Buchalla-Safir bound on $\gamma$ . I generalize it to the case where an upper bound on the phase of the penguin pollution is assumed. I apply the Buchalla-Safir bound, and its generalization, to the most recent data on CP violation in $B \to \pi^ + \pi^-$ .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02142-0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    The Lorentz and CPT violating effects on the $Z\rightarrow l^ + l^-$ decay (2005)
    Springer
    The European physical journal 40 (2005), S. 269-273 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We study the Lorentz and CPT violating effects on the branching ratio, the CPT violating asymmetry and the ratio of the decay width, including only the Lorentz violating effects, to the one obtained in the standard model, for the flavor dependent part of the lepton flavor conserving $Z\rightarrow l^ + l^-$ ( $l = e,\mu,\tau $ ) decay. The inclusion of the Lorentz and CPT violating effects in the standard model contribution are too small to be detected, since the corresponding coefficients are highly suppressed at the low energy scale.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02146-8
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Size of isospin breaking in charged $K_{\ell 4}$ decay (2005)
    Springer
    The European physical journal 40 (2005), S. 367-382 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We evaluate the size of isospin breaking corrections to form factors f and g of the $K_{\ell 4}$ decay process $K^ + \rightarrow\pi^ + \pi^-\ell^ + \nu_{\ell}$ which is actually measured by the extended NA48 setup at CERN. We found that, keeping apart the effect of Coulomb interaction, isospin breaking does not affect the moduli. This is due to the cancellation between corrections of electromagnetic origin and those generated by the difference between up and down quark masses. On the other hand, electromagnetism affects considerably the phases if the infrared divergence is dropped out using a minimal subtraction scheme. Consequently, the greatest care must be taken in the extraction of $\pi\pi$ phase shifts from experiment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02149-5
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Final-state radiation in electron-positron annihilation into a pion pair (2005)
    Springer
    The European physical journal 40 (2005), S. 41-54 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The process of e + e - annihilation into a $\pi^ + \pi^-$ pair with radiation of a photon is considered. The amplitude of the reaction $e^ + e^- \to \pi^ + \pi^- \gamma$ consists of the model independent initial-state radiation (ISR) and model dependent final-state radiation (FSR). The general structure of the FSR tensor is constructed from Lorentz covariance, gauge invariance and discrete symmetries in terms of the three invariant functions. To calculate these functions we apply chiral perturbation theory (ChPT) with vector and axial-vector mesons. The contribution of the $e^ + e^- \to \pi^ + \pi^- \gamma$ process to the muon anomalous magnetic moment is evaluated, and results are compared with the dominant contribution in the framework of a hybrid model, consisting of VMD and point-like scalar electrodynamics. The developed approach allows us also to calculate the $\pi^ + \pi^-$ charge asymmetry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02109-7
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Possible non-decoupling effects of heavy Higgs bosons in $e^ + e^- \to W^ + W^-$ within THDM (2005)
    Springer
    The European physical journal 40 (2005), S. 137-144 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We discuss the origin of the non-decoupling effects of the heavy Higgs bosons within the two Higgs doublet extension (THDM) of the standard model (SM) and illustrate it by means of the one-loop calculation of the differential cross sections of the process $e^ + e^- \to W^ + W^-$ in both the decoupling and the non-decoupling regimes. We argue that there are many regions in the THDM parametric space in which the THDM and SM predictions differ by several percents and such effects could, at least in principle, be testable at the future experimental facilities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02128-x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Neutrino dimuon production and the strangeness asymmetry of the nucleon (2005)
    Springer
    The European physical journal 40 (2005), S. 145-156 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We have performed the first global QCD analysis to include the CCFR and NuTeV dimuon data, which provide direct constraints on the strange and antistrange parton distributions, s(x) and $\bar{s}(x)$ . To explore the strangeness sector, we adopt a general parametrization of the non-perturbative $s(x), \bar{s}(x)$ functions satisfying basic QCD requirements. We find that the strangeness asymmetry, as represented by the momentum integral $[S^{-}]\equiv \int_0^1 x [s(x)-\bar{s}(x)] \mathrm dx$ , is sensitive to the dimuon data provided the theoretical QCD constraints are enforced. We use the Lagrange multiplier method to probe the quality of the global fit as a function of [S -] and find -0.001 〈 [S -] 〈 0.004. Representative parton distribution sets spanning this range are given. Comparisons with previous work are made.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2004-02099-4
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Heavy quark vacuum polarization: first two moments of the ${\mathcal{O}}(\alpha_s^3 n_f^2)$ contribution (2005)
    Springer
    The European physical journal 40 (2005), S. 361-366 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The vacuum polarization due to a virtual heavy quark pair and specifically the coefficients of its Taylor expansion in the external momentum are closely related to moments of the cross section for quark-antiquark pair production in electron-positron annihilation. Relating measurement and theoretically calculated Taylor coefficients, an accurate value for charm- and bottom-quark mass can be derived, once corrections from perturbative QCD are sufficiently well under control. Up to three-loop order these have been evaluated previously. We now present a subset of four-loop contributions to the lowest two moments, namely those from diagrams which involve two internal loops from massive and massless fermions coupled to virtual gluons, hence of order $\alpha_s^3 n_f^2$ . The calculation demonstrates the applicability of Laporta’s algorithm to four-loop vacuum diagrams with both massive and massless propagators and should be considered a first step towards the full evaluation of the order $\alpha_s^3$ contribution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02151-y
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Isospin breaking in $K \to 3 \pi$ decays III : Bremsstrahlung and fit to experiment (2005)
    Springer
    The European physical journal 40 (2005), S. 383-394 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We complete here our work on isospin violation in the $K \to 3 \pi$ system. We first calculate $K\to2\pi$ to the same order as we did $K \to 3 \pi$ in papers I and II of this series. This adds the effects of order G 27 p 2 (m u -m d ) and G 27 p 2 e 2 to earlier work. We calculate also the lowest order bremsstrahlung contributions, $K\to2\pi\gamma,3\pi\gamma$ . With these and our earlier results we perform a full fit to all available CP-conserving data in the $K\to2\pi,3\pi$ system including isospin violation effects. We perform these fits under various input assumptions as well as test the factorization and the vector dominance model for the weak NLO low energy constants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02155-7
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    A flavor symmetry for quasi-degenerate neutrinos: $L_\mu - L_\tau$ (2005)
    Springer
    The European physical journal 40 (2005), S. 259-268 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We consider the flavor symmetry $L_\mu - L_\tau$ for the neutrino mass matrix. The most general neutrino mass matrix conserving $L_\mu - L_\tau$ predicts quasi-degenerate neutrino masses with one maximal and two zero mixing angles. The presence of $L_\mu - L_\tau$ can also be motivated by the near-bimaximal form of the neutrino mixing matrix. Furthermore, it is a special case of $\mu \tau$ symmetric mass matrices. Breaking the flavor symmetry by adding a small flavor-blind term to the neutrino mass matrix and/or by applying radiative corrections is shown to reproduce the observed neutrino oscillation phenomenology. Both the normal and inverted mass ordering can be accommodated within this scheme. Moderate cancellation for neutrinoless double beta decay is expected. The observables |U e3|2 and $\vert 1/2 - \sin^2\theta_{23}\vert$ are proportional to the inverse of the fourth power of the common neutrino mass scale. We comment on whether the atmospheric neutrino mixing is expected to lie above or below $\pi/4$ . We finally present a model based on the see-saw mechanism which generates a light neutrino mass matrix with an (approximate) $L_\mu - L_\tau$ flavor symmetry. This is a minimal model with just one standard Higgs doublet and three heavy right-handed neutrinos. It needs only small values for the soft $L_\mu - L_\tau$ breaking terms to reproduce the phenomenological viable mass textures analyzed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02133-1
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Renormalization-group improved calculation of the $B\to X_s\gamma$ branching ratio (2005)
    Springer
    The European physical journal 40 (2005), S. 165-186 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Using results on soft-collinear factorization for inclusive B-meson decay distributions, a systematic study of the partial $B\to X_s\gamma$ decay rate with a cut $E_\gamma\ge E_0$ on photon energy is performed. For values of E 0 below about 1.9 GeV, the rate can be calculated without reference to shape functions using a multi-scale operator product expansion (MSOPE). The transition from the shape-function region to the MSOPE region is studied analytically. The resulting prediction for the $B\to X_s\gamma$ branching ratio depends on three large scales: m b , $\sqrt{m_b\Delta}$ , and $\Delta = m_b-2E_0$ . Logarithms associated with these scales are resummed at next-to-next-to-leading logarithmic order. While power corrections in $\Lambda_{\mathrm {QCD}}/\Delta$ turn out to be small, the sensitivity to the scale $\Delta\approx 1.1$ GeV (for $E_0\approx 1.8$ GeV) introduces significant perturbative uncertainties, which so far have been ignored. The new theoretical prediction for the $B\to X_s\gamma$ branching ratio with $E_\gamma\ge 1.8$ GeV is $\mbox{Br}(B\to X_s\gamma) = \smash{(3.38_{ -0.42}^{ + 0.31}\pm 0.31)}\times 10^{-4}$ , where the first error is an estimate of perturbative uncertainties and the second one reflects uncertainties in input parameters. With this cut $\smash{(89_{ -7}^{ + 6} \pm 1)}\%$ of all events are contained. When this fraction is combined with the previously best prediction for the total decay rate, one obtains $\mbox{Br}(B\to X_s\gamma) = (3.30_{ -0.35}^{ + 0.31}\pm 0.17)\times 10^{-4}$ , with a somewhat less conservative estimate of parametric uncertainties. The implications of larger theory uncertainties for new physics searches are briefly explored with the example of the type-II two-Higgs-doublet model, for which the lower bound on the charged-Higgs mass is reduced compared with previous estimates to approximately 200 GeV at 95% confidence level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02141-1
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Study of spin and decay-plane correlations of W bosons in the e + e $^-\rightarrow$ W + W- process at LEP (2005)
    Springer
    The European physical journal 40 (2005), S. 333-341 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Data collected at LEP at centre-of-mass energies $\sqrt{s} = 189-209$ GeV are used to study correlations of the spin of W bosons using $\mathrm{e}^ + \mathrm{e}^-\to \mathrm{W}^ + \mathrm{W}^-\to {\ensuremath{\ell\nu\mathrm{q\bar{q}}}}$ events. Spin correlations are favoured by data, and found to agree with the Standard Model predictions. In addition, correlations between the W-boson decay planes are studied in $\mathrm{e}^ + \mathrm{e}^-{}\to{}\mathrm{W}^ + \mathrm{W}^- \to{}{\ensuremath{\ell\nu\mathrm{q\bar{q}}}}$ and $\mathrm{e}^ + \mathrm{e}^-{}\to{}\mathrm{W}^ + \mathrm{W}^-{}\to{}{\ensuremath{\text{q}\bar{\text{q}}\text{q}\bar{\text{q}}}}{}$ events. Decay-plane correlations are measured to be consistent with the Standard Model predictions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02137-9
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Flavour-independent h0A0 search and two Higgs doublet model interpretation of neutral Higgs boson searches at LEP (2005)
    Springer
    The European physical journal 40 (2005), S. 317-332 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Upper limits on the cross-section of the pair-production process ${\ensuremath{{\mathrm{e}}^ + {\mathrm{e}}^-}} \to \mathrm{h}^0 \mathrm{A}^0$ , assuming 100 $\%$ branching fraction to hadrons, are derived from a new search for the $\mathrm{h}^0\mathrm{A}^0 \to $ hadrons final state, independently of the hadronic flavour of the decay products. This study, combined with previously published searches for the neutral Higgs bosons h0 and A0, is used to constrain the Type II Two Higgs Doublet Model (2HDM(II)) with no CP violation in the Higgs sector and no additional non-Standard Model particles besides the five Higgs bosons. The analysis combines LEP1 and LEP2 data collected with the OPAL detector up to the highest available centre-of-mass energies. The searches are sensitive to the $\mathrm{h}^0, \mathrm{A}^0 \to \mathrm{q\bar{q}}, {\ensuremath{\mathrm{g}\mathrm{g}}}, {\ensuremath{\tau^ + \tau^-}}$ and $\mathrm{h}^0\to\mathrm{A}^0\mathrm{A}^0$ decay modes of the Higgs bosons. A benchmark scan of the 2HDM(II) parameter space is performed. Large regions of the 2HDM(II) parameter space explored are excluded at the 95% CL in the ( $m_{\mathrm{h}}, m_{\mathrm{A}}), (m_{\mathrm{h}}, \tan{\beta})$ and $(m_{\mathrm{A}}, \tan{\beta})$ planes, using both direct neutral Higgs boson searches and indirect limits derived from Standard Model high precision measurements. The region $1 \lesssim m_{\mathrm{h}} \lesssim 55$ GeV and $3 \lesssim m_{\mathrm{A}} \lesssim 63$ GeV is excluded at 95 % CL, independently of $m_{\mathrm{h}}, m_{\mathrm{A}}, \tan{\beta}$ and for selected values of $\alpha$ which are representative of a complete $\alpha$ -scan.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjc/s2005-02122-4
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...