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  • Articles  (204)
  • Articles: DFG German National Licenses  (204)
  • Springer  (204)
  • 2005-2009  (204)
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  • Articles  (204)
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  • 1
    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
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  • 2
    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
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  • 3
    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
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  • 4
    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
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  • 5
    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
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  • 6
    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
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  • 7
    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
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  • 8
    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
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  • 9
    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
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  • 10
    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
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  • 11
    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
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  • 12
    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
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  • 13
    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
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  • 14
    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
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  • 15
    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
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  • 16
    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
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  • 17
    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
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  • 18
    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
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    Bioremediation by Composting of Heavy Oil Refinery Sludge in Semiarid Conditions (2006)
    Springer
    Biodegradation 17 (2006), S. 251-261 
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    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.
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    Lorentz symmetry breaking and planar effects from non-linear electrodynamics (2006)
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    The European physical journal 46 (2006), S. 247-254 
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    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.
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    URL: http://dx.doi.org/10.1140/epjc/s2006-02483-0
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    The Dalitz decay π0 → e+e– γ revisited (2006)
    Springer
    The European physical journal 46 (2006), S. 191-217 
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    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.
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    URL: http://dx.doi.org/10.1140/epjc/s2005-02466-7
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    Tree-unitarity bounds for THDM Higgs masses revisited (2006)
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    The European physical journal 46 (2006), S. 81-91 
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    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.
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    URL: http://dx.doi.org/10.1140/epjc/s2006-02472-3
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    Evaluating massive planar two-loop tensor vertex integrals (2006)
    Springer
    The European physical journal 46 (2006), S. 157-178 
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    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.
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    URL: http://dx.doi.org/10.1140/epjc/s2006-02478-9
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    Stationary phase corrections in the process of bosonization of multi-quark interactions (2006)
    Springer
    The European physical journal 46 (2006), S. 225-233 
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    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.
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    Dual parameterization of generalized parton distributions and a description of DVCS data (2006)
    Springer
    The European physical journal 46 (2006), S. 151-156 
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    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.
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    URL: http://dx.doi.org/10.1140/epjc/s2006-02491-0
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    Flavor coupled with chiral oscillations in the presence of an external magnetic field (2006)
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    The European physical journal 46 (2006), S. 113-122 
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    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.
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    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 
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    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
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    Forward jet production in deep inelastic scattering at HERA (2006)
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    The European physical journal 46 (2006), S. 27-42 
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    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.
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    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 
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    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 $0.66\pm0.10(\text{stat.})\pm0.05(\text{syst.})$ .
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    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 
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    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.
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    Supersymmetry parameter analysis: SPA convention and project (2006)
    Springer
    The European physical journal 46 (2006), S. 43-60 
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    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.
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    Strain-induced properties of epitaxial VOx thin films (2005)
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    The European physical journal 43 (2005), S. 195-200 
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    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We have grown VOx thin films on different substrates in order to investigate the influence of epitaxial strain on the transport properties. We found that the electric conductivity is much larger for films grown under compressive strain on SrTiO3 substrates, as compared to bulk material and VOx films grown under tensile strain on MgO substrates. A clear crossover from metallic to semiconducting behavior is observed when increasing the oxygen content x. Apparently, the application of strain induces a Mott-Hubbard insulator-to-metal transition in VOx〈1. The VOx/SrTiO3 films show an unexpected large positive magnetoresistance effect at low temperatures, which is not found in the VOx films grown under tensile strain on MgO or on a substrate with a similar lattice parameter.
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    Theory of neutron scattering for gapless neutral spin-1 collective mode in graphite (2005)
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    The European physical journal 43 (2005), S. 175-185 
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    ISSN: 1434-6036
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    Topics: Physics
    Notes: Abstract. Using tight binding band picture for 2D graphite, and the Hubbard interaction, recently we obtained a gapless, neutral spin-1 collective mode branch in graphite [Phys. Rev. Lett. 89, 016402]. In this paper we present a detailed RPA analysis of the Neutron Scattering cross section for this collective mode. Near K-point and very close to Γ-point, the intensity of neutron scattering peaks vanishes as q3. This is shown using a simple Dirac cone model for the graphite band structure, which captures the small-q behavior of the system. As we move away from the Γ- and K-points in the Brillouin zone of the collective mode momenta, we can identify our collective mode quanta with spin triplet excitons with the spatial extent of the order of a few to a couple of lattice parameter a, with more or less anisotropic character, which differs from point to point. We also demonstrate that the inclusion of the long range tail of the Coulomb interaction in real graphite, does not affect our spin-1 collective mode qualitatively. This collective mode could be probed at different energy scales by thermal, hot and epithermal neutron scattering experiments. However, the smallness of the calculated scattering intensity, arising from a reduced form factor of carbon 2pz orbital makes the detection challenging.
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    Magnetic AC susceptibility of stoichiometric and low zinc doped magnetite single crystals (2005)
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    The European physical journal 43 (2005), S. 201-212 
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    ISSN: 1434-6036
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    Topics: Physics
    Notes: Abstract. Systematic studies of AC susceptibility in a stoichiometric magnetite single crystal, in a series of low zinc doped magnetite (xZn 〈 0.04) and in nonstoichiometric magnetite samples (both single crystals and pellets) in the temperature range 4–300 K are presented. Measurements were performed in several AC fields ( $H_{AC}=0.2{-}20\ $ Oe) and at different frequencies (15–6000 Hz). It is suggested that the signal is primarily due to magnetic domain wall movement, strongly influenced by structural domains (twins). Two sets of anomalies were found: the first is associated with the Verwey transition and the second involves two different effects, one at 28 K, observed only in stoichiometric magnetite, and the other at 50 K. While the temperature position of the first anomaly (28 K) does not depend on frequency, the effect at 50 K is associated with an activation process, shifting to higher temperatures with increasing frequency. This last effect may be linked to the low temperature magnetoelectric effects terminating approximately at those temperatures. Qualitatively similar results have been observed by the Magnetic After Effect technique presented in the literature, that is associated with relaxation times that are 104 higher than those characteristic of our technique.
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    HSSH-model of Hole transfer in DNA (2005)
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    The European physical journal 43 (2005), S. 279-281 
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    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. A method based on a selfconsistent solution of a quantum-mechanical system with temperature fluctuations described by Langevin equations is developed to calculate the charge carrier mobility in DNA. To model the charge transfer in DNA, a combined Holstein – SSH Hamiltonian is considered. As an example the hole mobility is calculated at room temperature for synthetic poly (G)/poly (C) duplex with regard to main structural fluctuations.
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    Fermion kinetics in the Falicov-Kimball limit of the three-band Emery model (2005)
    Springer
    The European physical journal 43 (2005), S. 319-331 
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    Notes: Abstract. The three-band Emery model is reduced to a single-particle quantum model of Falicov-Kimball type, by allowing only up-spins to hop, and forbidding double occupation by projection. It is used to study the effects of geometric obstruction on mobile fermions in thermodynamic equilibrium. For low hopping overlap, there appears a plateau in the entropy, due to charge correlations, and related to real-space disorder. For large overlap, the equilibrium thermopower susceptibility remains anomalous, with a sign opposite to the one predicted from the single-particle density of states. The heat capacity and non-Fermi liquid response are discussed in the context of similar results in the literature. All results are obtained by evaluation of an effective single-particle free-energy operator in closed form. The method to obtain this operator is described in detail.
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    Quantum interference in nanotube electron waveguides (2005)
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    The European physical journal 43 (2005), S. 399-403 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We have calculated the quantum conductance of single-walled carbon nanotube (SWNT) waveguide by using a tight binding-based Green’s function approach. Our calculations show that the slow conductance oscillations as well as the fast conductance oscillations are manifestations of the intrinsic quantum interference properties of the conducting SWNTs, being independent of the defect and disorder of the SWNTs. And zigzag type tubes do not show the slow oscillations. The SWNT electron waveguide is also found to have distinctly different transport behavior depending on whether or not the length of the tube is commensurate with a (3N+1) rule, with N the number of basic carbon repeat units along the nanotube length.
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    The investigation of the magnetodielectric effect in multiferroic ferroelectromagnets (2005)
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    The European physical journal 43 (2005), S. 333-338 
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    Topics: Physics
    Notes: Abstract. In multiferroic ferroelectromagnets, microscopic coupling interaction between the ferroelectric and magnetic order results in the macroscopic correlation between the dielectric and magnetic properties, which is defined as magnetodielectric effect. If we classify multiferroic ferroelectromagnets as two kinds: ferroelectric-ferromagnets and ferroelectric-antiferromagnets, we find the magnetodielectric behavior of these two kinds of ferroeletromagnets show obvious difference. We analyze the origin of the different magnetodielectric behavior and find that the fluctuation of the spin-pair correlation plays a critical role. Soft-mode theory based on DIFFOUR model and the mean-field theory are combined to deal with multiferroic ferroelectromagnetic system.
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    Dimensional reduction of the Abelian Higgs Carroll-Field-Jackiw model (2005)
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    The European physical journal 38 (2005), S. 511-519 
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    Notes: Abstract. Taking as a starting point a Lorentz non-invariant abelian Higgs model defined in 1 + 3 dimensions, we carry out its dimensional reduction to D = 1 + 2, obtaining a new planar model composed by a Maxwell-Chern-Simons-Proca gauge sector, a massive scalar sector, and a mixing term (involving the fixed background $v^{\mu}$ ) that imposes the Lorentz violation to the reduced model. The propagators of the scalar and massive gauge field are evaluated and the corresponding dispersion relations determined. Based on the poles of the propagators, a causality and unitarity analysis is carried out at tree level. We then show that the model is totally causal, stable and unitary.
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    Measurement of the energy dependence of hadronic jet rates and the strong coupling $\alpha_s$ from the four-jet rate with the DELPHI detector at LEP (2005)
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    The European physical journal 38 (2005), S. 413-426 
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    Topics: Physics
    Notes: Abstract. Hadronic events from the data collected with the DELPHI detector at LEP within the energy range from 89 Gev to 209 Gev are selected, their jet rates are determined and compared to predictions of four different event generators. One of them is the recently developed APACIC + + generator which performs a massive matrix element calculation matched to a parton shower followed by string fragmentation. The four-jet rate is used to measure $\alpha_s$ in the next-to-leading-order approximation yielding $${\alpha_s(M_Z^2)} = 0.1175 \pm 0.0030. $$ The running of $\alpha_s$ determined by using four-jet events has been tested. The logarithmic energy slope is measured to be $$ \frac{{\mathrm{d}}\alpha_s^{-1}}{{\mathrm{d}} \log E_{\mathrm {cm}}} = 1.14 \pm 0.36. $$ Since the analysis is based on four-jet final states it represents an alternative approach to previous DELPHI $\alpha_s$ measurements using event shape distributions.
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    Inclusive production of D + , D 0, D s + and D * + mesonsin deep inelastic scattering at HERA (2005)
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    The European physical journal 38 (2005), S. 447-459 
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    Notes: Abstract. Inclusive production cross sections are measured in deep inelastic scattering at HERA for meson states composed of a charm quark and a light antiquark or the charge conjugate. The measurements cover the kinematic region of photon virtuality 2 〈 Q 2 〈 100 Gev2, inelasticity 0.05 〈 y 〈 0.7, D meson transverse momenta $p_t(D) \ge 2.5$ Gev and pseudorapidity $\vert\eta(D)\vert \le 1.5$ . The identification of the D-meson decays and the reduction of the combinatorial background profit from the reconstruction of displaced secondary vertices by means of the H1 silicon vertex detector. The production of charmed mesons containing the light quarks u,d and s is found to be compatible with a description in which the hard scattering is followed by a factorisable and universal hadronisation process.
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    Measurement of prompt photon cross sections in photoproduction at HERA (2005)
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    The European physical journal 38 (2005), S. 437-445 
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    Notes: Abstract. Results are presented on the photoproduction of isolated prompt photons, inclusively and associated with jets, in the $\gamma p$ center of mass energy range 142 〈 W 〈 266 GeV. The cross sections are measured for the transverse momentum range of the photons $5 〈 E_T^{\gamma} 〈 10$ GeV and for associated jets with E T jet 〉 4.5 GeV. They are measured differentially as a function of $E_T^{\gamma}, E_T^{\mathrm{jet}}$ , the pseudorapidities $\eta^{\gamma}$ and $\eta^{\mathrm{jet}}$ and estimators of the momentum fractions $x_{\gamma}$ and x p of the incident photon and proton carried by the constituents participating in the hard process. In order to further investigate the underlying dynamics, the angular correlation between the prompt photon and the jet in the transverse plane is studied. Predictions by perturbative QCD calculations in next to leading order are about $30\%$ below the inclusive prompt photon data after corrections for hadronisation and multiple interactions, but are in reasonable agreement with the results for prompt photons associated with jets. Comparisons with the predictions of the event generators PYTHIA and HERWIG are also presented.
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    Coherent production of pairs of parabosons of order 2 (2005)
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    The European physical journal 39 (2005), S. 109-121 
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    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.
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    On the boundary conditions as Dirac constraints (2005)
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    The European physical journal 39 (2005), S. 123-127 
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    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.
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    Concerning the Landau pole in 3-3-1 models (2005)
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    The European physical journal 39 (2005), S. 101-107 
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    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.
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    Split supersymmetry at colliders (2005)
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    The European physical journal 39 (2005), S. 229-243 
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    Notes: Abstract. We consider the collider phenomenology of split-supersymmetry models. Despite the challenging nature of the signals in these models the long-lived gluino can be discovered with masses above 2 TeV at the LHC. At a future linear collider we will be able to observe the renormalization group effects from split supersymmetry, using measurements of the neutralino and chargino masses and cross sections.
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    Casimir effect for gauge fields in spaces with negative constant curvature (2005)
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    The European physical journal 39 (2005), S. 249-252 
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    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.
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    Non-Abelian color dielectric - towards the effective model of the low energy QCD (2005)
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    The European physical journal 39 (2005), S. 185-193 
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    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.
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    Generalized parton distributions from nucleon form factor data (2005)
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    The European physical journal 39 (2005), S. 1-39 
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    Notes: Abstract. We present a simple empirical parameterization of the x- and t-dependence of generalized parton distributions at zero skewness, using forward parton distributions as input. A fit to experimental data for the Dirac, Pauli and axial form factors of the nucleon allows us to discuss quantitatively the interplay between longitudinal and transverse partonic degrees of freedom in the nucleon (“nucleon tomography”). In particular we obtain the transverse distribution of valence quarks at given momentum fraction x. We calculate various moments of the distributions, including the form factors that appear in the handbag approximation to wide-angle Compton scattering. This allows us to estimate the minimal momentum transfer required for reliable predictions in that approach to be around $\vert t\vert \simeq 3 {\rm GeV}^2$ . We also evaluate the valence contributions to the energy-momentum form factors entering Ji’s sum rule.
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    Spin effects in the electron structure functions (2005)
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    The European physical journal 39 (2005), S. 55-59 
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    Notes: Abstract. The electron structure functions are studied in polarized e + e - scattering. The formulae for longitudinally and transversely polarized electrons are presented. The smallness of the electron mass leads to negligible cross-sections and asymmetries in some cases. Positivity constraints on the structure functions and parton densities are constructed and discussed. The cross-section asymmetries at very high energies, where the inclusion of all elecroweak bosons is necessary, are calculated. Numerical examples, using the asymptotic solutions for the parton densities inside the electron, are presented.
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    Two loop $\overline{{\rm MS}}$ gluon pole mass from the LCO formalism (2005)
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    The European physical journal 39 (2005), S. 61-69 
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    Notes: Abstract. We compute the pole mass of the gluon in QCD from the local composite operator formalism at two loops in the $\overline{{\rm MS}}$ renormalization scheme. For the Yang-Mills theory an estimate of the mass at two loops is $2.13\Lambda_{\overline{{\rm MS}}}$ .
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    Parton distributions incorporating QED contributions (2005)
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    The European physical journal 39 (2005), S. 155-161 
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    Notes: Abstract. We perform a global parton analysis of deep inelastic and related hard-scattering data, including ${{\mathcal{O}}}(\alpha_{\rm QED})$ corrections to the parton evolution. Although the quality of the fit is essentially unchanged, there are two important physical consequences. First, the different DGLAP evolution of u and d type quarks introduces isospin violation, i.e. $u^p \neq d^n$ , which is found to be unambiguously in the direction to reduce the NuTeV $\sin^2\theta_W$ anomaly. A second consequence is the appearance of photon parton distributions $\gamma(x,Q^2)$ of the proton and the neutron. In principle these can be measured at HERA via the deep inelastic scattering processes $e N \to e\gamma X$ ; our predictions are in agreement with the present data.
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    Gauge theories with non-unitary parallel transporters: a soluble Higgs model* (2005)
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    The European physical journal 39 (2005), S. 483-497 
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    Notes: Abstract. It has been proposed to abandon the requirement that parallel transporters in gauge theories are unitary (or pseudo-orthogonal). This leads to a geometric interpretation of Vierbein fields as parts of gauge fields, and non-unitary parallel transport in extra directions yields Higgs fields. In such theories, the holonomy group H is larger than the gauge group G. Here we study a one-dimensional model with fermions which retains only the extra dimension, and which is soluble in the sense that its renormalization group flow may be exactly computed, with G = SU(2) and non-compact $H\subseteq GL(2,\mathbf{C})$ , or G = U(2), H = GL(2,C). In all cases the asymptotic behavior of the Higgs potential is computed, and with one possible exception for G = SU(2), H = GL(2,C), there is a flow of the action from a UV fixed point which describes a SU(2)-gauge theory with unitary parallel transporters, to a IR fixed point. We explain how exponential mass ratios of fermions of different flavor can arise through spontaneous symmetry breaking, within the general framework.
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    Non-equivalence between Heisenberg XXZ spin chain and Thirring model (2005)
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    The European physical journal 39 (2005), S. 511-518 
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    Notes: Abstract. The Bethe ansatz equations for the spin 1/2 Heisenberg XXZ spin chain are numerically solved, and the energy eigenvalues are determined for the antiferromagnetic case. We examine the relation between the XXZ spin chain and the massless Thirring model, and show that the spectrum of the XXZ spin chain has a gapless excitation while the regularized Thirring model calculated with the Bogoliubov transformation method has a finite gap. This finite gap spectrum is also confirmed by the Bethe ansatz solution of the massless Thirring model.
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    Radiative return at $\Phi$ - and B-factories: FSR for muon pair production at next-to-leading order (2005)
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    The European physical journal 39 (2005), S. 411-420 
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    Notes: Abstract. Muon pair production through the radiative return is of importance for a measurement of the hadronic production cross section in two ways: it provides an independent calibration and it may give rise to an important background for the measurement of the pion form factor. With this motivation the Monte Carlo event generator PHOKHARA is extended to include next-to-leading order radiative corrections to the reaction $e^ + e^-\to \mu^ + \mu^-\gamma$ . Furthermore, virtual ISR corrections to FSR from pions are introduced, which extends the applicability of the generator into a new kinematical regime. Finally, the effect of photon vacuum polarization is introduced into this new version of the generator.
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    Effective action and Hawking flux from covariant perturbation theory (2005)
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    The European physical journal 40 (2005), S. 275-286 
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    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.
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    Correlator of heavy-quark currents at small q 2 in the large- $\beta_0$ limit (2005)
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    The European physical journal 40 (2005), S. 157-164 
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    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.
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    Analyses of k t distributions at RHIC by means of some selected statistical and stochastic models (2005)
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    The European physical journal 40 (2005), S. 243-250 
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    Notes: Abstract. The new data on k t distributions obtained at RHIC are analyzed by means of selected models of statistical and stochastic origin in order to estimate their importance in providing new information on the hadronization process, in particular on the value of the temperature at freeze-out to the hadronic phase.
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    $ B \to D^{(*)}$ transitions in a quark model (2005)
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    The European physical journal 40 (2005), S. 193-197 
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    Notes: Abstract. We propose a constituent quark model to evaluate heavy decay constants and form factors relevant for $ B \to D^{(*)}$ semileptonic transitions. We show that the model reproduces the scaling laws dictated by the spin-flavor symmetry in the heavy quark limit and describes quite well the experimental data.
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    The difference between n-dimensional regularization and n-dimensional reduction in QCD (2005)
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    The European physical journal 40 (2005), S. 199-203 
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    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.
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    Size of isospin breaking in charged $K_{\ell 4}$ decay (2005)
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    The European physical journal 40 (2005), S. 367-382 
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    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.
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    Measurements of the charge asymmetry of the Dalitz plot parameters for $K^{\pm}\to\pi^{\pm}\pi^0\pi^0$ decays (2005)
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    The European physical journal 40 (2005), S. 343-347 
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    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 ${(0.2 \pm 1.9)\cdot 10^{-3}}$ .
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    Two-parton twist-3 factorization in perturbative QCD (2005)
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    The European physical journal 40 (2005), S. 395-417 
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    Notes: Abstract. We prove the collinear factorization theorem for the process $\pi\gamma^*\to\pi$ at the twist-3 level in the covariant gauge by means of the Ward identity, concentrating on the two-parton case. It is shown that soft divergences cancel and collinear divergences are grouped into the pseudo-scalar and pseudo-tensor two-parton twist-3 pion distribution amplitudes. The delicate summation of a complete set of diagrams for achieving factorization in momentum, spin, and color spaces is emphasized. The proof is then extended to the exclusive semileptonic decay $B\to\pi l\nu$ , assuming the hard scale to be of $O\smash{\bigl(\sqrt{\bar{\Lambda} M_B}\bigr)}$ , where $\bar{\Lambda}$ is a hadronic scale and M B the B meson mass. We explain the distinction between the factorization of collinear divergences for a pion distribution amplitude and of soft divergences for a B meson distribution amplitude. The gauge invariance and universality of the two-parton twist-3 pion distribution amplitudes are confirmed. The proof presented here can accommodate the leading twist-2 case. We then compare our proof with that performed in the framework of soft-collinear effective theory.
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    H/A Higgs mixing in CP-noninvariant supersymmetric theories (2005)
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    The European physical journal 40 (2005), S. 555-564 
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    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.
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    Study of the neutron quantum states in the gravity field (2005)
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    The European physical journal 40 (2005), S. 479-491 
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    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.
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    Isospin breaking in $K \to 3 \pi$ decays III : Bremsstrahlung and fit to experiment (2005)
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    The European physical journal 40 (2005), S. 383-394 
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    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.
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    Study of spin and decay-plane correlations of W bosons in the e + e $^-\rightarrow$ W + W- process at LEP (2005)
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    The European physical journal 40 (2005), S. 333-341 
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    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.
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    The neutron decay retardation spectrometer aSPECT: Electromagnetic design and systematic effects (2005)
    Springer
    The European physical journal 23 (2005), S. 135-146 
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    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.
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    From solar proton burning to pionic deuterium through the Nambu-Jona-Lasinio model of light nuclei (2005)
    Springer
    The European physical journal 23 (2005), S. 1-6 
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    ISSN: 1434-601X
    Keywords: 11.10.Ef Lagrangian and Hamiltonian approach ; 13.75.Gx Pion-baryon interactions ; 36.10.-k Exotic atoms and molecules (containing mesons, muons, and other unusual particles) ; 26.65.+t Solar neutrinos
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Within the Nuclear Nambu-Jona-Lasinio model of light nuclei (the NNJL model), describing strong low-energy nuclear interactions, we compute the width of the energy level of the ground state of pionic deuterium. The theoretical value fits well the experimental data. Using the cross-sections for the reactions νe + d → p + p + e- and νe + d → p + n + νe, computed in the NNJL model, and the experimental values of the events of these reactions, detected by the SNO Collaboration, we compute the boron neutrino fluxes. The theoretical values agree well with the experimental data and the theoretical predictions within the Standard Solar Model by Bahcall. We argue the applicability of the constraints on the astrophysical factor for the solar proton burning, imposed by helioseismology, to the width of the energy level of the ground state of pionic deuterium. We show that the experimental data on the width satisfy these constraints. This testifies an indirect measurement of the recommended value of the astrophysical factor for the solar proton burning in terrestrial laboratories in terms of the width of the energy level of the ground state of pionic deuterium.
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    Dispersion of incoherent spectral features in systems with strong electron-phonon coupling (2005)
    Springer
    The European physical journal 43 (2005), S. 11-18 
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    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We study (inverse) photoemission from systems with strong coupling of doped carriers to phonons. Using an adiabatic approximation, we develop a method for calculating spectra. This method is particularly simple for systems where the electron-phonon coupling can be neglected in the initial state, e.g., the undoped t-J model. The theory then naturally explains why the electron-phonon coupling just leads to a broadening of spectra calculated without electron-phonon coupling, without changing the dispersion. This is in agreement with recent angle-resolved photoemission spectroscopy (ARPES) on undoped cuprates, and it supports the interpretation in terms of strong electron-phonon interaction. The theory also shows that for systems with strong electron-phonon coupling in the initial state, the result cannot in general be related to the spectrum obtained without electron-phonon coupling.
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    Electronic structure of the Sr0.4Ca13.6Cu24O41 incommensurate compound (2005)
    Springer
    The European physical journal 43 (2005), S. 29-37 
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    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We extracted, from strongly-correlated ab-initio calculations, a complete model for the chain subsystem of the Sr0.4Ca13.6Cu24O41 incommensurate compound. A second neighbor t-J+V model has been determined as a function of the fourth crystallographic parameter τ, for both low and room temperature crystallographic structures. The analysis of the obtained model shows the crucial importance of the structural modulations on the electronic structure through the on-site energies and the magnetic interactions. The structural distortions are characterized by their long range effect on the cited parameters that hinder the reliability of analyses such as BVS. One of the most striking results is the existence of antiferromagnetic nearest-neighbor interactions for metal-ligand-metal angles of 90○. A detailed analysis of the electron localization and spin arrangement is presented as a function of the chain to ladder hole transfer and of the temperature. The obtained spin arrangement is in agreement with antiferromagnetic correlations in the chain direction at low temperature.
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    Bulk mediated surface diffusion: non Markovian desorption with finite first moment (2005)
    Springer
    The European physical journal 43 (2005), S. 65-71 
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    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Here we address a fundamental issue in surface physics: the dynamics of adsorbed molecules. We study this problem when the particle’s desorption is characterized by a non Markovian process, while the particle’s adsorption and its motion in the bulk are governed by a Markovian dynamics. We study the diffusion of particles in a semi-infinite cubic lattice, and focus on the effective diffusion process at the interface z = 1. We calculate analytically the conditional probability to find the particle on the z=1 plane as well as the surface dispersion as functions of time. The comparison of these results with Monte Carlo simulations show an excellent agreement.
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    Dielectric resonances of ordered passive arrays (2005)
    Springer
    The European physical journal 43 (2005), S. 81-92 
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    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The electrical and optical properties of ordered passive arrays, constituted of inductive and capacitive components, are usually deduced from Kirchhoff’s rules. Under the assumption of periodic boundary conditions, comparable results may be obtained via an approach employing transfer matrices. In particular, resonances in the dielectric spectrum are demonstrated to occur if all eigenvalues of the transfer matrix of the entire array are unity. The latter condition, which is shown to be equivalent to the habitual definition of a resonance in impedance for an array between electrodes, allows for a convenient and accurate determination of the resonance frequencies, and may thus be used as a tool for the design of materials with a specific dielectric response. For the opposite case of linear arrays in a large network, where periodic boundary condition do not apply, several asymptotic properties are derived. Throughout the article, the derived analytic results are compared to numerical models, based on either Exact Numerical Renormalisation or the spectral method.
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    Ripple formation over a sand bed submitted to a laminar shear flow (2005)
    Springer
    The European physical journal 43 (2005), S. 283-294 
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    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We investigate the process of ripple formation in a viscous fluid when a sand bed is submitted to a laminar shear flow. We propose a new description for the sand transport which takes into account the fact that the transport rate does not adapt instantaneously to a change of the fluid velocity due to grain inertia. It introduces a new length, called here after equilibrium length leq, corresponding to the distance needed for a immobile grain to equilibrate its velocity with that of the fluid. The transport rate is therefore found to depend not only on the fluid shear stress and bed slope (as usually assumed) but also on grain inertia. Within the framework of this model we analyzed the mechanisms of the sand bed instability. It is found that the instability results from the competition between the destabilizing effect of fluid inertia and the stabilizing ones of grain inertia and bed slope. We derive analytical scaling laws for the most amplified wavelength, its growth rate and phase velocity. We found in particular that at small particle Reynolds number Rep, the most amplified wavelength scales as the viscous length lν defined as $\sqrt{\nu/\gamma}$ (where γ is the shear rate and ν the fluid viscosity) and at large Rep it scales as the equilibrium length leq. Our results are compared with available experimental data.
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    Diagram technique for finding of vertex functions in the Landau theory of heteropolymer liquids (2005)
    Springer
    The European physical journal 43 (2005), S. 251-269 
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    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The problem on finding the coefficients of the Landau free energy expansion into the power series of parameter of order has been considered for solutions and melts of linear heteropolymers whose molecules comprise several types monomeric units arranged stochastically. The presence of such a quenched structural disorder places this problem outside the framework of the traditional statistical physics inviting for its solution special approaches. One of them, based on the replica concept and actively engaged in theoretical physics of disordered systems, has been invoked in this paper to derive expressions for the vertex functions in the Landau theory of heteropolymer liquids. An algorithm has been formulated which permits one resorting to the simple diagram technique to write down expressions for these functions of any order in terms of the statistical characteristics of chemical quenched structure of polymer molecules. Explicit expressions for the contributions to the Landau free energy up to the fourth degree of order parameters for polymer systems with an arbitrary structural disorder have been presented to illustrate this general algorithm. Its potentialities have been also exemplified for the melt of random m-component copolymer where exact analytical formulas for these contributions up to n=6 at an arbitrary m have been derived for the first time.
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    Uncompensated antiferromagnetic structure of Ho2Ni2Pb (2005)
    Springer
    The European physical journal 43 (2005), S. 163-174 
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    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We have studied the magnetic structure of the orthorhombic compound Ho2Ni2Pb by means of neutron diffraction in zero field and in magnetic fields up to 4.5 T. Both powder and single-crystalline samples were used. Previous bulk measurements suggest two distinct magnetic phase transitions: one at TN = 7.0 K and the other at 4.8 K. Our neutron diffraction measurements, which were made in the range 1.5-20 K, showed that Ho2Ni2Pb has a collinear magnetic structure with unequal number of up and down Ho moments that are aligned parallel and antiparallel to the c axis. At the lowest temperatures the Ho moments are equal in size, each 8.3 μB in agreement with magnetization data. The magnetic structure can be described as having a 5a ×b ×c magnetic unit cell. Below Ts = 3.0 K the structure is squared up. A smooth development of all the magnetic moment magnitudes indicates that the magnetic structure remains in principle the same over the whole temperature range, the “phase transition” around 4.8 K can be identified as an inflection point in the temperature dependence of one of the Ho moments. With increasing temperature there is a clear development towards a simple transverse sine-wave modulated magnetic structure that is established just below TN.
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    Moment instabilities in multidimensional systems with noise (2005)
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    The European physical journal 43 (2005), S. 221-242 
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    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract. We present a systematic study of moment evolution in multidimensional stochastic difference systems, focusing on characterizing systems whose low-order moments diverge in the neighborhood of a stable fixed point. We consider systems with a simple, dominant eigenvalue and stationary, white noise. When the noise is small, we obtain general expressions for the approximate asymptotic distribution and moment Lyapunov exponents. In the case of larger noise, the second moment is calculated using a different approach, which gives an exact result for some types of noise. We analyze the dependence of the moments on the system’s dimension, relevant system properties, the form of the noise, and the magnitude of the noise. We determine a critical value for noise strength, as a function of the unperturbed system’s convergence rate, above which the second moment diverges and large fluctuations are likely. Analytical results are validated by numerical simulations. Finally, we present a short discussion of the extension of our results to the continuous time limit.
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    Frequency clustering of coupled phase oscillators on small-world networks (2005)
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    The European physical journal 43 (2005), S. 243-250 
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    ISSN: 1434-6036
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    Notes: Abstract. We analyze the phenomenon of frequency clustering in a system of coupled phase oscillators. The oscillators, which in the absence of coupling have uniformly distributed natural frequencies, are coupled through a small-world network, built according to the Watts-Strogatz model. We study the time evolution and determine variations in the transient times depending on the disorder of the network and on the coupling strength. We investigate the effects of fluctuations in the average frequencies, and discuss the definition of the threshold for synchronization. We characterize the structure of clusters and the distribution of cluster sizes in the synchronization transition, and define suitable order parameters to describe the aggregation of the oscillators as the network disorder and the coupling strength change. The non-monotonic behavior observed in some order parameters is related to fluctuations in the mean frequencies.
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    Interaction effects on persistent current of ballistic cylindrical nanostructures (2005)
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    The European physical journal 43 (2005), S. 405-419 
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    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We investigate clean cylindrical nanostructures with an applied longitudinal static magnetic field. The ground state of these systems becomes degenerate for particular values of the field due to Aharonov-Bohm effect. The Coulomb interaction introduces couplings between the electronic configurations. Consequently, depending on particular selection rules, the ground state may become, in the interacting case, a many body state at the degeneracy points: a gap is then opened. To study this problem, we propose a variational multireference wave function which goes beyond the Hartree-Fock approximation. Using this ansatz, in addition to the replacements of some crossings by avoided crossings, two other important effects of the electron-electron interaction are pointed out: (i) the long-range part of the Coulomb potential tends to shift the position in magnetic field of the crossing or avoided crossing points and, (ii) at the points of degeneracy or near degeneracy, the interaction can drive the system from a singlet to a triplet state inducing new real crossing points in the ground state energy curve as function of the field. In any case, the crossing points that are due to either orbital or spin effects, should manifest themselves in various experiments as sudden changes in the response of the system (magnetoconductance, magnetopolarisability, ...) when the magnetic field is tuned.
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    Polaron properties in ternary group-III nitride mixed crystals (2005)
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    The European physical journal 43 (2005), S. 339-345 
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    ISSN: 1434-6036
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    Topics: Physics
    Notes: Abstract. Polaron properties are studied in bulk wurtzite nitride ternary mixed crystals AxB1-xN (A, B = Al, Ga, In) with the use of a dielectric continuum Fröhlich-like electron-phonon interaction Hamiltonian. The polaronic self-trapping energy and effective mass are analytically derived by taking the mixing properties of the LO and TO polarizations due to the anisotropy effect into account in the mono-phonon approximation. The numerical computation has been performed for the wurtzite ternary mixed crystal materials InxGa1-xN, AlxGa1-xN, and AlxIn1-xN as functions of the composition x. The results show that the polaronic self-trapping energies in the wurtzite structures are bigger than that in zinc-blende structures for the materials calculated. It is also found that the structure anisotropy increases the electron-phonon interaction in wurtizte nitride semiconductors. The results indicate that the LO-like phonon influence on the polaronic self-trapping energy and effective mass is dominant, and the anisotropy effect is obvious.
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    Dimer site-bond percolation on a square lattice (2005)
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    The European physical journal 43 (2005), S. 363-368 
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    Topics: Physics
    Notes: Abstract. A generalization of the pure site and pure bond percolation problems in which pairs of nearest neighbor sites (site dimers) and linear pairs of nearest neighbor bonds (bond dimers) are independently occupied at random on a square lattice is studied. We called this model as dimer site-bond percolation. Motivated by considerations of cluster connectivity, we have used two distinct schemes (denoted as $S\cap B$ and $S\cup B$ ) for dimer site-bond percolation. In $S \cap B$ ( $S \cup B$ ), two points are said to be connected if a sequence of occupied sites and (or) bonds joins them. By using finite-size scaling theory, data from $S \cap B$ and $S \cup B$ are analyzed in order to determine i) the phase boundary between the percolating and non-percolating regions and ii) the numerical values of the critical exponents of the phase transition occurring in the system. The results obtained are discussed in comparison with the corresponding ones for classical monomer site-bond percolation.
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    Ground-state correlations and finite temperature properties of the transverse Ising model (2005)
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    The European physical journal 43 (2005), S. 373-378 
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    Notes: Abstract. We present a semi-analytic study of Ising spins on a simple square or cubic lattice coupled to a transverse magnetic field of variable strength. The formal analysis employs correlated basis functions (CBF) theory to investigate the properties of the corresponding N-body ground and excited states. For these states we discuss two different ansaetze of correlated trial wave functions and associated longitudinal and transverse excitation modes. The formalism is then generalized to describe the spin system at nonzero temperatures with the help of a suitable functional approximating the Helmholtz free energy. To test the quality of the functional in a first step we perform numerical calculations within the extended formalism but ignore spatial correlations. Numerical results are reported on the energies of the longitudinal and the transverse excitation modes at zero temperature, on critical data at finite temperatures, and on the optimized spontaneous magnetization as a function of temperature and external field strength.
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    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 
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    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.
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    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 
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    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.
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    Leading-particle suppression in high energy nucleus-nucleus collisions (2005)
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    The European physical journal 38 (2005), S. 461-474 
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    Source: Springer Online Journal Archives 1860-2000
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    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.
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    B decays into light scalar particles and glueball (2005)
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    The European physical journal 39 (2005), S. 71-86 
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    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 ${b\to sg}$ .
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    Quark-meson SU(3) model in a Tamm-Dancoff inspired approximation (2005)
    Springer
    The European physical journal 38 (2005), S. 483-494 
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    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.
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    Diffractive $\gamma \gamma$ production at hadron colliders (2005)
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    The European physical journal 38 (2005), S. 475-482 
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    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.
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    Zero-curvature formalism of supersymmetric principal chiral model (2005)
    Springer
    The European physical journal 38 (2005), S. 521-526 
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    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
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    Measurement of triple gauge boson couplings at an $e\gamma$ -collider (2005)
    Springer
    The European physical journal 38 (2005), S. 427-436 
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    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
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    Comments on spin operators and spin-polarization states of 2 + 1 fermions (2005)
    Springer
    The European physical journal 39 (2005), S. 245-248 
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    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
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    Hidden local symmetry and chiral effective theory for vector and axial-vector mesons (2005)
    Springer
    The European physical journal 39 (2005), S. 201-208 
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    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
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    Inelastic $J/\psi$ and $\Upsilon$ hadroproduction (2005)
    Springer
    The European physical journal 39 (2005), S. 163-171 
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    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
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    Exclusive decuplet-baryon pair production in two-photon collisions (2005)
    Springer
    The European physical journal 39 (2005), S. 173-178 
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    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
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    Twisted mass quarks and the phase structure of lattice QCD (2005)
    Springer
    The European physical journal 39 (2005), S. 421-433 
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    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
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    Jet production in pA and AA collisions in the perturbative QCD pomeron model (2005)
    Springer
    The European physical journal 39 (2005), S. 451-464 
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    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
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    Improved phase space treatment of massive multi-particle final states (2005)
    Springer
    The European physical journal 39 (2005), S. 439-450 
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    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
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    Observing higher-dimensional black holes at the LHC (2005)
    Springer
    The European physical journal 39 (2005), S. 503-509 
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    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
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    Orbifold compactification and solutions of M-theory from Milne spaces (2005)
    Springer
    The European physical journal 39 (2005), S. 519-524 
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    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
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    Isospin constraints from/on $B \to \pi\pi$ (2005)
    Springer
    The European physical journal 39 (2005), S. 397-409 
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    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
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