ALBERT

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The LPCTrap experiment uses an open Paul trap which was built to enable precision measurements in the beta decay of radioactive ions. The initial goal was the precise measurement of the beta-neutrino angular correlation coefficient in the decay of 〈sup〉6〈/sup〉He . Its geometry results from a careful optimization of the harmonic potential created by cylindrical electrodes. It supersedes previously considered geometries that presented a smaller detection solid angle to the beta particle and the recoiling ion. We describe here the methods which were used for the potential optimization, and we present the measured performances in terms of trapping time, cloud size and temperature, and space charge related limits. The properties of the ion cloud at equilibrium are investigated by a simple numerical simulation using hard sphere collisions, which additionally gives insights on the trapping loss mechanism. The interpretation for the observed trapping lifetimes is further corroborated by a model recently developed for ion clouds in Paul traps. The open trap shall serve other projects. It is currently used for commissioning purpose in the TRAPSENSOR experiment and is also considered in tests of the Standard Model involving the beta decay of polarized 〈sup〉23〈/sup〉Mg and 〈sup〉39〈/sup〉Ca ion in the frame of the MORA experiment. The latter tests require in-trap polarization of the ions and further optimization of the trapping and detection setup. Based on the results of the simulations and of their interpretation, different improvements of the trapping setup are discussed.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We have discussed the dynamical instability of a collapsing spherical object in the Einstein Gauss-Bonnet gravity. The linear perturbation method is used to construct the collapse equation from the field equations and conservation equations. The instability range for adiabatic index 〈span〉 〈span〉\( \Gamma\)〈/span〉 〈/span〉 has been investigated by considering Newtonian and Post-Newtonian limits. The relativistic correction of dissipation reduces instability, while the Newtonian and post-Newtonian approximations due to dissipation increase the instability range of adiabatic index 〈span〉 〈span〉\( \Gamma\)〈/span〉 〈/span〉. The Gauss-Bonnet term 〈span〉 〈span〉\( \alpha\)〈/span〉 〈/span〉 plays a dominant role in increasing the instability of the spherical object.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉New experimental prompt fission neutron and fragment data for 〈sup〉235〈/sup〉U(n, f ) measured at JRC-Geel offer the possibility of a detailed validation of the PbP and sequential emission modelings. The very good agreement of the prompt neutron multiplicity matrices 〈span〉 〈span〉\(\nu (A,\mathrm{TKE})\)〈/span〉 〈/span〉 with these data constitutes a primary and valuable validation of the models themselves. Other data from this experiment are also well described by both model results obtained by averaging the corresponding multi-parametric matrices over an 〈span〉 〈span〉\(Y(A,\mathrm{TKE})\)〈/span〉 〈/span〉 distribution measured at JRC-Geel. This is considered as a secondary validation (〈em〉i.e.〈/em〉, of the models together with the 〈span〉 〈span〉\(Y(A,\mathrm{TKE})\)〈/span〉 〈/span〉 distribution).〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We study the partial decay widths of the charmonium states ( 〈span〉 〈span〉\( J/\psi\)〈/span〉 〈/span〉, 〈span〉 〈span〉\( \psi (3686)\)〈/span〉 〈/span〉, 〈span〉 〈span〉\( \psi (3770)\)〈/span〉 〈/span〉, 〈span〉 〈span〉\( \chi_{c0}\)〈/span〉 〈/span〉, 〈span〉 〈span〉\( \chi_{c2}\)〈/span〉 〈/span〉 to 〈span〉 〈span〉\( D\bar{D}\)〈/span〉 〈/span〉 (〈span〉 〈span〉\( D^+D^-\)〈/span〉 〈/span〉 or 〈span〉 〈span〉\( D^0\bar{D^0}\)〈/span〉 〈/span〉) in isospin asymmetric nuclear matter, in the presence of strong magnetic fields. The in-medium partial decay widths of charmonium states to 〈span〉 〈span〉\( D\bar{D}\)〈/span〉 〈/span〉 are calculated within a light quark-antiquark pair creation model, namely the 〈sup〉3〈/sup〉〈em〉P〈/em〉〈sub〉0〈/sub〉 model, using the in-medium masses of the charmonia as well as 〈em〉D〈/em〉 and 〈span〉 〈span〉\( \bar{D}\)〈/span〉 〈/span〉 mesons in the magnetized nuclear matter, obtained within a chiral effective model. The presence of a magnetic field leads to Landau quantization of the energy levels of the proton in the nuclear medium. The effects of magnetic field and isospin asymmetry on the charmonium decay widths to 〈span〉 〈span〉\( D\bar{D}\)〈/span〉 〈/span〉 are found to be quite prominent. The effects of the anomalous magnetic moments have also been taken into consideration for obtaining the in-medium masses of these heavy flavour mesons, used to calculate the partial decay widths of the charmonium states. The medium modifications of the charmonium decay widths can have observable consequences on the production of the charmed mesons in high energy asymmetric heavy ion collision experiments.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉High-precision mass measurements of stable and beta-decaying nuclides 〈sup〉52-57〈/sup〉Cr, 〈sup〉55〈/sup〉Mn, 〈sup〉56,59〈/sup〉Fe, 〈sup〉59〈/sup〉Co, 〈sup〉75, 77-79〈/sup〉Ga, and the lanthanide nuclides 〈sup〉140〈/sup〉Ce, 〈sup〉140〈/sup〉Nd, 〈sup〉160〈/sup〉Yb, 〈sup〉168〈/sup〉Lu, 〈sup〉178〈/sup〉Yb have been performed with the Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The new data are entered into the Atomic Mass Evaluation and improve the accuracy of masses along the valley of stability, strengthening the so-called backbone. The mass of neutron-deficient 〈sup〉168〈/sup〉Lu in its isomeric state has been measured directly. The mass of neutron-rich 〈sup〉178〈/sup〉Yb indicates a change of nuclear structure approaching the double harmonic-oscillator shell closure for 〈span〉 〈span〉\( Z=70\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( N=112\)〈/span〉 〈/span〉.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Multi-messenger observations of neutron star (NS) mergers have the potential to revolutionize nuclear astrophysics. They will improve our understanding of nucleosynthesis, provide insights about the equation of state (EOS) of strongly interacting matter at high densities, and enable tests of the theory of gravity and of dark matter. Here, we focus on the EOS, where both gravitational waves (GWs) from neutron-star mergers and X-ray observations from space-based detectors such as NICER will provide more stringent constraints on the structure of neutron stars. Furthermore, recent advances in nuclear theory have enabled reliable calculations of the EOS at low densities using effective field theory based Hamiltonians and advanced techniques to solve the quantum many-body problem. In this paper, we address how the first observation of GWs from GW170817 can be combined with modern calculations of the EOS to extract useful insights about the EOS of matter encountered inside neutron stars. We analyze the impact of various uncertainties, the role of phase transitions in the NS core, and discuss how future observations will improve our understanding of dense matter.〈/p〉

Description: 〈p〉After publication of the paper, the authors noticed some errors in the list of authors and in the list of affiliations. Their correct version is given in this erratum.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Using separable potentials for the 〈span〉 〈span〉\( \bar{K}N\)〈/span〉 〈/span〉 - 〈span〉 〈span〉\( \pi\Sigma\)〈/span〉 〈/span〉 interaction, we investigated four-body kaonic nuclear systems, such as 〈span〉 〈span〉\( K^{-}ppn\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( K^{-}K^{-}pp\)〈/span〉 〈/span〉 , with the Faddeev AGS method in the momentum representation. The Faddeev calculations are based on the quasi-particle method and the method of energy-dependent pole expansion was used to obtain the separable representation for the integral kernels in the three- and four-body equations. Different types of 〈span〉 〈span〉\( \bar{K}N\)〈/span〉 〈/span〉 - 〈span〉 〈span〉\( \pi\Sigma\)〈/span〉 〈/span〉 potentials based on phenomenological and chiral 〈em〉SU〈/em〉(3) approach are used and it was shown that the kaonic nuclear systems under consideration are tightly bound.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉This paper summarises a comprehensive Monte Carlo simulation study for precision resonance energy scan measurements. Apart from the proof of principle for natural width and line shape measurements of very narrow resonances with PANDA, the achievable sensitivities are quantified for the concrete example of the charmonium-like 〈em〉X〈/em〉(3872) state discussed to be exotic, and for a larger parameter space of various assumed signal cross-sections, input widths and luminosity combinations. PANDA is the only experiment that will be able to perform precision resonance energy scans of such narrow states with quantum numbers of spin and parities that differ from 〈span〉 〈span〉\( J^{PC} = 1^{--}\)〈/span〉 〈/span〉.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉A pomeron with 〈span〉 〈span〉\( Q^2\)〈/span〉 〈/span〉 dependent intercept has been introduced to the Regge amplitude. This kind of intercept produces the variation of the vector meson cross section with energy at fixed 〈span〉 〈span〉\( Q^2\)〈/span〉 〈/span〉 . A coefficient for a single term amplitude is introduced to provide the variation with 〈span〉 〈span〉\( Q^2\)〈/span〉 〈/span〉 at fixed energy. For the 〈span〉 〈span〉\( \rho\)〈/span〉 〈/span〉 meson, this coefficient is given by the form of coupling of the exchanged pomeron to the virtual photon-〈span〉 〈span〉\( \rho\)〈/span〉 〈/span〉 meson vertex. In the soft region, the model shows a good agreement with the data. In the hard region the model agrees with the data at high energies, but at the lower values of energy the cross section is suppressed due to the threshold energy. For 〈span〉 〈span〉\( \varphi\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( j/\psi\)〈/span〉 〈/span〉 productions, a similar approach to that of the 〈span〉 〈span〉\( \rho\)〈/span〉 〈/span〉 meson is used but the coefficient in this case is constructed in terms of three parameters. These parameters are fixed by experimental data. A comparison with the data and with the two-pomeron model indicates that the one-pomeron model describes the data as good as the two-pomeron model and involves only three parameters.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Understanding the origin and dynamics of hadron structure and in turn that of atomic nuclei is a central goal of nuclear physics. This challenge entails the questions of how does the roughly 1GeV mass-scale that characterizes atomic nuclei appear; why does it have the observed value; and, enigmatically, why are the composite Nambu-Goldstone (NG) bosons in quantum chromodynamics (QCD) abnormally light in comparison? In this perspective, we provide an analysis of the mass budget of the pion and proton in QCD; discuss the special role of the kaon, which lies near the boundary between dominance of strong and Higgs mass-generation mechanisms; and explain the need for a coherent effort in QCD phenomenology and continuum calculations, in exa-scale computing as provided by lattice QCD, and in experiments to make progress in understanding the origins of hadron masses and the distribution of that mass within them. We compare the unique capabilities foreseen at the electron-ion collider (EIC) with those at the hadron-electron ring accelerator (HERA), the only previous electron-proton collider; and describe five key experimental measurements, enabled by the EIC and aimed at delivering fundamental insights that will generate concrete answers to the questions of how mass and structure arise in the pion and kaon, the Standard Model's NG modes, whose surprisingly low mass is critical to the evolution of our Universe.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We propose a theoretical approach to the consideration of the Hamiltonian with pairing forces using the technique of finite boson representation. We show that a simultaneous description of the pairing vibrational state in 〈sup〉56〈/sup〉Ni and the pairing rotational states with the isospin 〈span〉 〈span〉\( T=0\)〈/span〉 〈/span〉 in the neighboring 〈span〉 〈span〉\( N=Z\)〈/span〉 〈/span〉 nuclei is possible if the pairing Hamiltonian takes into account only isovector monopole pairing. However, the calculated energies of the pairing rotational states of 〈span〉 〈span〉\( N=Z\)〈/span〉 〈/span〉 nuclei obtained from 〈sup〉56〈/sup〉Ni by adding (removing) 12 or more nucleons exceed significantly the experimental values. A possible reason for this discrepancy is discussed.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Early data on 〈span〉 〈span〉\( K^-\)〈/span〉 〈/span〉 induced reactions off protons are collected and used in a coupled-channel partial-wave analysis (PWA). Data that had been published in the form of Legendre coefficients are included in the PWA. In a 〈em〉primary〈/em〉 fit using 〈span〉 〈span〉\( 3^{\ast}\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( 4^{\ast}\)〈/span〉 〈/span〉 resonances only, we observe some significant discrepancies with the data. In a systematic search for new 〈span〉 〈span〉\( \Lambda\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( \Sigma\)〈/span〉 〈/span〉 hyperon resonances, additional candidates are found. The significance of the known and of the additional resonances is evaluated. Seventeen resonances listed with 〈span〉 〈span〉\( 1^{\ast}\)〈/span〉 〈/span〉 or 〈span〉 〈span〉\( 2^{\ast}\)〈/span〉 〈/span〉 and one resonance listed with 〈span〉 〈span〉\( 3^{\ast}\)〈/span〉 〈/span〉 in the Review of Particle Physics cannot be confirmed, five new hyperons are suggested. The partial-wave amplitudes deduced in this analysis are compared to those from other analyses.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The isomeric yield ratios (IR) of 〈sup〉196m, g〈/sup〉Au in the 〈sup〉197〈/sup〉Au(n, 2n) reaction at the average neutron energies (〈span〉 〈span〉\( \langle E_{n}\rangle\)〈/span〉 〈/span〉) of 14.4, 21.8 and 29.5 MeV have been measured by using the off-line gamma-ray spectrometric technique. The neutron beams were obtained by using the 〈sup〉9〈/sup〉Be(p, n) reaction with the proton energies of 25, 35 and 45 MeV from the MC-50 cyclotron at KIRAMS. The IR values at different neutron energies were also calculated from the cross sections values based on TENDL-2017 library and are found to be in agreement around 10–18 MeV but not at higher energy. The IR values of 〈sup〉196m, g〈/sup〉Au at the neutron energies of 21.8 and 29.5 MeV have been measured for the first time. The present data along with the literature data at other energies in the 〈sup〉197〈/sup〉Au(n, 2n) reaction are compared with the similar data in the 〈sup〉197〈/sup〉Au(〈span〉 〈span〉\( \gamma\)〈/span〉 〈/span〉, n) reaction to examine the role of entrance channel parameters and occurrence of non-compound or pre-equilibrium process at higher projectile energy.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The relevant interaction energies for astrophysical radiative capture reactions are very low, much below the repulsive Coulomb barrier. This leads to low cross sections, low counting rates in γ-ray detectors, and therefore the need to perform such experiments at ion accelerators placed in underground settings, shielded from cosmic rays. Here, the feasibility of such experiments in the new shallow-underground accelerator laboratory in tunnels VIII and IX of the Felsenkeller site in Dresden, Germany, is evaluated. To this end, the no-beam background in three different types of germanium detectors, 〈em〉i.e.〈/em〉 a Euroball/Miniball triple cluster and two large monolithic detectors, is measured over periods of 26–66 days. The cosmic-ray induced background is found to be reduced by a factor of 500–2400, by the combined effects of, first, the 140 meters water equivalent overburden attenuating the cosmic muon flux by a factor of 40, and second, scintillation veto detectors gating out most of the remaining muon-induced effects. The new background data are compared to spectra taken with the same detectors at the Earth’s surface and at other underground sites. Subsequently, the beam intensity from the cesium sputter ion source installed in Felsenkeller has been studied over periods of several hours. Based on the background and beam intensity data reported here, for the example of the 〈sup〉12〈/sup〉C(α,γ)〈sup〉16〈/sup〉O reaction it is shown that highly sensitive experiments will be possible.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The excited states of 〈sup〉169〈/sup〉Tm have been studied via the 〈sup〉169〈/sup〉Tm(〈sup〉32〈/sup〉S,〈sup〉32〈/sup〉S〈sup〉′〈/sup〉)〈sup〉169〈/sup〉Tm〈sup〉*〈/sup〉 reaction at the beam energy of 164MeV. The 〈span〉 〈span〉\(\gamma\)〈/span〉 〈/span〉-rays were detected using the Indian National Gamma Array (INGA) setup, composed of 19 Compton-suppressed clover HPGe detectors. A new level scheme of 〈sup〉169〈/sup〉Tm with 11 newly placed 〈span〉 〈span〉\( \gamma\)〈/span〉 〈/span〉-rays has been proposed. A band crossing in the 〈span〉 〈span〉\( \pi [541]1/2^{-}\)〈/span〉 〈/span〉 band and several interband 〈em〉E〈/em〉1 transitions between this and the 〈span〉 〈span〉\( \pi [411]1/2^{+}\)〈/span〉 〈/span〉 ground-state band have been observed for the first time in this nucleus. The role of the 〈span〉 〈span〉\(N=98\)〈/span〉 〈/span〉 deformed shell gap has been discussed by comparing the band crossing parameters of the negative parity bands in Tm and other neighboring nuclei. The origin of the interband 〈em〉E〈/em〉1 transitions has been investigated in terms of coupling to octupole degrees of freedom. The shape evolution of the Tm isotopes around 〈span〉 〈span〉\( N=98\)〈/span〉 〈/span〉 have been studied in the projected and cranked shell model approaches, both of which predict a change in shape from an axial prolate to a triaxial one after band crossing in these nuclei. The new data and the calculations help to understand the unusual structural phenomena reported for the nuclei with 〈span〉 〈span〉\( N=98\)〈/span〉 〈/span〉.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉MiniCLEAN is a single-phase liquid argon dark matter experiment. During the initial cooling phase, impurities within the cold gas (〈span〉 〈span〉\( 〈 140\)〈/span〉 〈/span〉 K) were monitored by measuring the scintillation light triplet lifetime, and ultimately a triplet lifetime of 〈span〉 〈span〉\( 3.480 \pm 0.001 (stat.) \pm 0.064 (sys.)\)〈/span〉 〈/span〉 μs was obtained, indicating ultra-pure argon. This is the longest argon triplet time constant ever reported. The effect of quenching of separate components of the scintillation light is also investigated.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The crust-core (CC) phase transition of neutron stars is studied within a unified meta-modeling of the nuclear Equation of State (EoS). The variational equations in the crust are solved within a Compressible Liquid-Drop (CLD) approach, with surface parameters consistently optimized for each EoS set on experimental nuclear mass data. When EoS parameters are taken from known Skyrme or RMF functionals, the transition point of those models is nicely reproduced as expected. The probability distribution of EoS parameters and of the transition density and pressure is determined with a Bayesian analysis, where the prior is given by an uncorrelated distribution of parameters considering the present empirical uncertainties, and constraints are applied both from neutron star physics and 〈em〉ab initio〈/em〉 predictions. We show that the properties of the CC transition point are largely independent of the high density properties of the EoS, while 〈em〉ab initio〈/em〉 EoS calculations of neutron and symmetric matter are far more constraining. The surface tension of extremely neutron rich matter, which remains poorly known, is the most influential parameter for the CC transition point. This explains the large dispersion of existing predictions of the CC transition point. Fixing the isospin dependence of the surface tension to a reasonable but somewhat arbitrary value, strong correlations with isovector EoS parameters (〈span〉 〈span〉\( L_{sym}\)〈/span〉 〈/span〉, 〈span〉 〈span〉\( K_{sym}\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( Q_{sym}\)〈/span〉 〈/span〉) are recovered. Within the present experimental and theoretical uncertainties on those parameters, we estimate the transition density as 〈span〉 〈span〉\( n_{t}= 0.072\pm 0.011\)〈/span〉 〈/span〉 fm〈sup〉-3〈/sup〉 and the transition pressure as 〈span〉 〈span〉\( P_{t}=0.339\pm 0.115\)〈/span〉 〈/span〉 MeV fm〈sup〉-3〈/sup〉.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We report on new measurements of the electric Generalized Polarizability (GP) of the proton 〈span〉 〈span〉\( \alpha_{E}\)〈/span〉 〈/span〉 in a kinematic region where a puzzling dependence on momentum transfer has been observed, and we have found that 〈span〉 〈span〉\( \alpha_E = (5.3 \pm 0.6_{stat} \pm 1.3_{sys}) 10^{-4}\)〈/span〉 〈/span〉 fm〈sup〉3〈/sup〉 at 〈span〉 〈span〉\( Q^{2}=0.20\)〈/span〉 〈/span〉 (GeV/〈em〉c〈/em〉)〈sup〉2〈/sup〉. The new measurements, when considered along with the rest of the world data, suggest that 〈span〉 〈span〉\( \alpha_E\)〈/span〉 〈/span〉 can be described by either a local plateau or by an enhancement in the region 〈span〉 〈span〉\( Q^2=0.20\)〈/span〉 〈/span〉 (GeV/〈em〉c〈/em〉)〈sup〉2〈/sup〉 to 0.33 (GeV/〈em〉c〈/em〉)〈sup〉2〈/sup〉. The experiment also provides the first measurement of the Coulomb quadrupole amplitude in the 〈span〉 〈span〉\( N \rightarrow \Delta\)〈/span〉 〈/span〉 transition through the exploration of the 〈span〉 〈span〉\( p(e,e'p)\gamma\)〈/span〉 〈/span〉 reaction. The new measurement gives 〈span〉 〈span〉\( CMR = (-4.4 \pm 0.8_{stat} \pm 0.6_{sys})\%\)〈/span〉 〈/span〉 at 〈span〉 〈span〉\( Q^2=0.20\)〈/span〉 〈/span〉 (GeV/〈em〉c〈/em〉)〈sup〉2〈/sup〉 and is consistent with the results from the pion electroproduction world data. It has been obtained using a completely different extraction method, and therefore represents a strong validation test of the world data model uncertainties.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The 〈span〉 〈span〉\(\omega\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\(\phi\)〈/span〉 〈/span〉 mesons dominantly decay outside the nucleus because their decay length is much larger than the dimension of the nucleus. Therefore, the medium modification of the above mesons is studied through their absorption in the nucleus. CLAS Collaboration at Jefferson Laboratory (Jlab) has investigated the absorption of the 〈span〉 〈span〉\(\omega\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( \phi\)〈/span〉 〈/span〉 mesons by measuring the nuclear transparency ratios for them in the 〈span〉 〈span〉\(\gamma A \rightarrow \omega (\phi) X \rightarrow e^{+}e^{-}X\)〈/span〉 〈/span〉 reaction. The nuclear transparency ratios for both 〈span〉 〈span〉\(\omega\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\(\phi\)〈/span〉 〈/span〉 mesons in the above reactions have been calculated and compared with the experimental findings, reported from Jlab, to estimate the 〈span〉 〈span〉\(\omega\)〈/span〉 〈/span〉 meson nucleon and 〈span〉 〈span〉\(\phi\)〈/span〉 〈/span〉 meson nucleon cross sections in the nucleus.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The 〈sup〉152〈/sup〉Sm(〈sup〉16〈/sup〉O, 5n)〈sup〉163〈/sup〉Yb reaction at a beam energy of 93 MeV was used to study the excited states of 〈sup〉163〈/sup〉Yb with the AFRODITE 〈span〉 〈span〉\(\gamma\)〈/span〉 〈/span〉-ray spectrometer at iThemba LABS. The level scheme of 〈sup〉163〈/sup〉Yb has been extended and new rotational bands established. The band based on the ground-state has been extended from a spin of 11/2〈sup〉-〈/sup〉 to spin 43/2〈sup〉-〈/sup〉. A high-〈em〉K〈/em〉 band based on the neutron [505]11/2〈sup〉-〈/sup〉 Nilsson orbital has been observed and is reported for the first time in this work. Additional new states in 〈sup〉163〈/sup〉Yb were observed which all decay to the yrast band. Some of these states are placed in a sequence which is conjectured to be a 〈span〉 〈span〉\( \gamma\)〈/span〉 〈/span〉 band involving a coupling with the 〈em〉i〈/em〉〈sub〉13/2〈/sub〉[642]5/2〈sup〉+〈/sup〉 neutron orbital. The band structures are discussed with reference to Cranked Shell Model (CSM) calculations and a systematic comparison with the neighbouring nuclei.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The STEREO experiment measures the electron antineutrino spectrum emitted in a research reactor using the inverse beta decay reaction on H nuclei in a gadolinium loaded liquid scintillator. The detection is based on a signal coincidence of a prompt positron and a delayed neutron capture event. The simulated response of the neutron capture on gadolinium is crucial for the comparison with data, in particular in the case of the detection efficiency. Among all stable isotopes, 〈sup〉155〈/sup〉Gd and 〈sup〉157〈/sup〉Gd have the highest cross sections for thermal neutron capture. The excited nuclei after the neutron capture emit gamma rays with a total energy of about 8MeV. The complex level schemes of 〈sup〉156〈/sup〉Gd and 〈sup〉158〈/sup〉Gd are a challenge for the modeling and prediction of the deexcitation spectrum, especially for compact detectors where gamma rays can escape the active volume. With a new description of the Gd (n,〈span〉 〈span〉\( \gamma\)〈/span〉 〈/span〉) cascades obtained using the FIFRELIN code, the agreement between simulation and measurements with a neutron calibration source was significantly improved in the STEREO experiment. A database of ten millions of deexcitation cascades for each isotope has been generated and is now available for the user.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The one loop polarization insertions for the kaon and the 〈span〉 〈span〉\(\phi\)〈/span〉 〈/span〉 mesons are evaluated in a hadronic medium as functions of the field intensity and the baryonic density. For this purpose an effective chiral model of the hadronic interaction is used, supplemented with a phenomenological 〈em〉K〈/em〉-〈span〉 〈span〉\(\phi\)〈/span〉 〈/span〉 interaction. The propagators of the charged particles include the full effect of the coupling to the magnetic field, and the anomalous magnetic moments are taken into account for the baryon fields. The effective masses as well as the decay widths are introduced and examined as functions of matter density and the magnetic intensity.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The difference between observed cross sections of the evaporation residues (ER) of the 〈sup〉34〈/sup〉S + 〈sup〉208〈/sup〉Pb and 〈sup〉36〈/sup〉S + 〈sup〉206〈/sup〉Pb reactions formed in the 2n and 3n channels has been explained by two reasons related with the entrance channel characteristics of these reactions. The first reason is that the capture cross section of the latter reaction is larger than the one of the 〈sup〉34〈/sup〉S + 〈sup〉208〈/sup〉Pb reaction since the nucleus-nucleus potential is more attractive in the 〈sup〉36〈/sup〉S + 〈sup〉206〈/sup〉Pb reaction due to two more neutrons in isotope 〈sup〉36〈/sup〉S. The second reason is the difference in the heights of the intrinsic fusion barrier 〈span〉 〈span〉\(B^{\ast}_{\mathrm{fus}}\)〈/span〉 〈/span〉 appearing on the fusion trajectory by nucleon transfer between nuclei of the DNS formed after the capture. The value of 〈span〉 〈span〉\( B^{\ast}_{\mathrm{fus}}\)〈/span〉 〈/span〉 calculated for the 〈sup〉34〈/sup〉S + 〈sup〉208〈/sup〉Pb reaction is higher than the one obtained for the 〈sup〉36〈/sup〉S + 〈sup〉206〈/sup〉Pb reaction. This is due to the difference between the 〈span〉 〈span〉\( N/Z\)〈/span〉 〈/span〉-ratios in the light fragments of the DNS formed during the capture in these reactions. The 〈span〉 〈span〉\( N/Z\)〈/span〉 〈/span〉-ratio has been found by the solution of the transport master equations for the proton and neutron distributions between fragments of the DNS formed at the capture with the different initial neutron numbers 〈span〉 〈span〉\( N=18\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( N=20\)〈/span〉 〈/span〉 for the reactions with the 〈sup〉34〈/sup〉S and 〈sup〉36〈/sup〉S, respectively.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We calculate the 〈span〉 〈span〉\( \delta f\)〈/span〉 〈/span〉 correction to the one particle distribution function in the presence of magnetic field and non-zero shear viscosity within the relaxation time approximation. The 〈span〉 〈span〉\( \delta f\)〈/span〉 〈/span〉 correction is found to be electric charge dependent. Subsequently, we also calculate one longitudinal and four transverse shear viscous coefficients as a function of the dimensionless Hall parameter 〈span〉 〈span〉\( \chi_{H}\)〈/span〉 〈/span〉 in the presence of the magnetic field. We find that a proper linear combination of the shear viscous coefficients calculated in this work scales with the result obtained from Grad’s moment method in [#!Denicol:2018rbw!#]. The calculation of the invariant yield of 〈span〉 〈span〉\( \pi^{-}\)〈/span〉 〈/span〉 in a simple Bjorken expansion with cylindrical symmetry shows no noticeable change in spectra due to the 〈span〉 〈span〉\( \delta f\)〈/span〉 〈/span〉 correction for realistic values of the magnetic field and relaxation time. However, when transverse expansion is taken into account using a blast wave type flow field we found noticeable change in spectra and elliptic flow coefficients due to the 〈span〉 〈span〉\( \delta f\)〈/span〉 〈/span〉 correction. The 〈span〉 〈span〉\( \delta f\)〈/span〉 〈/span〉 is also found to be very sensitive to the magnitude of magnetic field. Hence we think it is important to take into account the 〈span〉 〈span〉\( \delta f\)〈/span〉 〈/span〉 correction in more realistic numerical magnetohydrodynamics simulations.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉An empirical formula is proposed for the two-proton decay half-lives. This study is an extension of the empirical formula reported recently by us for calculating the logarithmic half-lives of one-proton emitters. A similar four-parameter formula as a function of angular momentum is proposed for the two-proton emitters. The parameters of the formula are fitted using the results of the effective liquid drop model (ELDM). The obtained formula is found to agree fairly well with the known experimental values of the half-lives as well as with other theoretical model predictions. Apart from the experimentally known 2-p emitters, the results using the formula are found to compare well within an order magnitude with the results of the ELDM. Further calculations are carried out in the heavy and superheavy region for the prediction of one and two-proton emitters.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Models based on 〈em〉SU〈/em〉(6) symmetry breaking and large N〈sub〉c〈/sub〉 limit provide relations between the pion cloud contributions to the 〈span〉 〈span〉\(\gamma^{\ast} N \rightarrow \Delta (1232)\)〈/span〉 〈/span〉 quadrupole form factors, electric (G〈sub〉E〈/sub〉) and Coulomb (G〈sub〉C〈/sub〉), and the neutron electric form factor G〈sub〉En〈/sub〉, suggesting that those form factors are dominated by the same physical processes. Those relations are improved in order to satisfy a fundamental constraint between the electric and Coulomb quadrupole form factors in the long wavelength limit, when the photon three-momentum vanishes (Siegert’s theorem). Inspired by those relations, we study alternative parametrizations for the neutron electric form factor. The parameters of the new form are then determined by a combined fit to the G〈sub〉En〈/sub〉 and the 〈span〉 〈span〉\( \gamma^{\ast} N \rightarrow \Delta (1232)\)〈/span〉 〈/span〉 quadrupole form factor data. We obtain a very good description of the G〈sub〉E〈/sub〉 and G〈sub〉C〈/sub〉 data when we combine the pion cloud contributions with small valence quark contributions to the 〈span〉 〈span〉\( \gamma^{\ast} N \rightarrow \Delta (1232)\)〈/span〉 〈/span〉 quadrupole form factors. The best description of the data is obtained when the second momentum of G〈sub〉En〈/sub〉 is 〈span〉 〈span〉\( r_{n}^{4} \simeq -0.4\)〈/span〉 〈/span〉 fm〈sup〉4〈/sup〉. We conclude that the square radii associated with G〈sub〉E〈/sub〉 and G〈sub〉C〈/sub〉, 〈span〉 〈span〉\( r_{E}^{2}\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( r_{C}^{2}\)〈/span〉 〈/span〉, respectively, are large, revealing the long extension of the pion cloud. We conclude also that those square radii are related by 〈span〉 〈span〉\( r_{E}^{2} - r_{C}^{2} = 0.6 \pm 0.2\)〈/span〉 〈/span〉 fm〈sup〉2〈/sup〉. The last result is mainly the consequence of the pion cloud effects and Siegert’s theorem.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The role of deformations and orientations is studied in cluster decays of various radioactive nuclei leading to doubly magic 〈sup〉100〈/sup〉Sn or 〈sup〉132〈/sup〉Sn daughter nucleus, using the preformed cluster model (PCM). This model treats the cluster emission process via tunnelling across the potential barrier, the cluster/fragment being preformed with a relative probability 〈span〉 〈span〉\( P_0\)〈/span〉 〈/span〉. With the incorporation of deformation and orientation effects, the fragmentation potential, the penetration path and related barrier characteristics get significantly modified, due to which both the preformation probability 〈span〉 〈span〉\( P_0\)〈/span〉 〈/span〉 and penetrability 〈em〉P〈/em〉 of the emitting cluster get influenced. The calculated half-lives of the decaying clusters calculated using PCM are found to be within the upper limits of the present experiments. The influence of deformations and orientations on Sn radioactivity is also seen in terms of various barrier characteristics such as barrier modification, barrier height, etc. Moreover, the role of different nuclear proximity potentials, 〈em〉i.e.〈/em〉, Prox 77, Prox 88 and Prox 00, is analyzed in the context of potential energy surfaces (PES) in the ground-state decay of parent nucleus. The behavior of PES is explored including, as well as without including, the shell corrections in the binding energies, which in turn help to explore the importance of doubly magic closed shell configuration of daughter and cluster nuclei. The possible role of higher order multipole deformations (〈em〉i.e.〈/em〉, up to 〈span〉 〈span〉\( \beta_{4i}\)〈/span〉 〈/span〉) is also analyzed in view of the fragmentation path and barrier tunnelling characteristics.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We study the 〈span〉 〈span〉\( B^{+} \rightarrow J/\psi \omega K^{+}\)〈/span〉 〈/span〉 reaction, and show that it is driven by the presence of two resonances, the 〈em〉X〈/em〉(3940) and 〈em〉X〈/em〉(3930), that are of molecular nature and couple most strongly to 〈span〉 〈span〉\( D^{\ast} \bar{D}^{\ast}\)〈/span〉 〈/span〉, but also to 〈span〉 〈span〉\( J/\psi\omega\)〈/span〉 〈/span〉. Because of that, in the 〈span〉 〈span〉\( J/\psi\omega\)〈/span〉 〈/span〉 mass distribution we find a peak related to the excitation of the resonances and a cusp with large strength at the 〈span〉 〈span〉\( D^{\ast} \bar{D}^{\ast}\)〈/span〉 〈/span〉 threshold.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Cross-sections and their isomeric ratios (〈span〉 〈span〉\( \sigma_{\mathrm{m}}/\sigma_{\mathrm{g}}\)〈/span〉 〈/span〉) for the 〈sup〉185〈/sup〉Re(n, 2n)〈sup〉184m〈/sup〉Re and 〈sup〉185〈/sup〉Re(n, 2n)〈sup〉184g〈/sup〉Re reactions in the 13–15 MeV range were measured. The neutron activation technique was applied using the K-400 neutron generator at the Chinese Academy of Engineering Physics (CAEP). Natural Re samples and Nb monitor foils were activated jointly to determine the reaction cross-section and the incident neutron flux. The 〈sup〉3〈/sup〉H(d, n)〈sup〉4〈/sup〉He reaction was used to generate the neutron beam. The pure cross-section of the ground state was derived from the absolute cross-section of the metastable state using residual nuclear decay analysis. Numerical calculations using the nuclear-model-based computer code TALYS-1.8 with six level density models were used to obtain 〈sup〉185〈/sup〉Re(n, 2n)〈sup〉184m, g〈/sup〉Re reaction excitation functions and their isomeric cross-section ratios. Finally, experimentally determined cross-sections were compared with corresponding literature data.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉In high-energy nucleus-nucleus collisions, it is difficult to measure the contributions of resonance strong decay and weak decay to the final measured hadrons as well as the corresponding effects on some physical observables. To provide a reference from statistical thermal model, we performed a systematic analysis for the energy dependence of particle yield and yield ratios in Au + Au collisions. We found that the primary fraction of final hadrons decreases with increasing collision energy and somehow saturates around 〈span〉 〈span〉\(\sqrt{s_{{\rm NN}}} = 10\)〈/span〉 〈/span〉 GeV, indicating a limiting temperature in hadronic interactions. The fraction of strong or weak decay for final hadrons shows a different energy dependence behavior comparing to the primarily produced hadrons. These energy dependences of various particle yield and yield ratios from strong or weak decay can provide us with baselines for many hadronic observables in high-energy nucleus-nucleus collisions.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We calculate the nucleon parameters in symmetric nuclear matter employing the QCD sum rules approach. We focus on the average energy per nucleon and study the equilibrium states of the matter. We treat the matter as a relativistic system of interacting nucleons. Assuming the dependence of the nucleon mass on the light quark mass 〈span〉 〈span〉\(m_{q}\)〈/span〉 〈/span〉 to be more important than that of nucleon interactions we find that the contribution of the relativistic nucleons to the scalar quark condensate can be expressed as that caused by the nucleon matrix element multiplied by the density dependent factor 〈span〉 〈span〉\(F(\rho)\)〈/span〉 〈/span〉 caused by the relativistic motion of nucleons composing the matter. We demonstrate that there are no equilibrium states while we include only the condensates with dimension 〈span〉 〈span〉\(d\leq 3\)〈/span〉 〈/span〉. There are equilibrium states if we include the lowest order radiative corrections and the condensates with 〈span〉 〈span〉\(d\leq 4\)〈/span〉 〈/span〉. They manifest themselves for the nucleon sigma term 〈span〉 〈span〉\(\sigma_{N} 〉 60\)〈/span〉 〈/span〉 MeV. Including the condensates with 〈span〉 〈span〉\(d\leq 6\)〈/span〉 〈/span〉 we find equilibrium states of nuclear matter for 〈span〉 〈span〉\( \sigma_{N} 〉 41\)〈/span〉 〈/span〉 MeV. In all cases the equilibrium states are due to influence of the relativistic motion of nucleons on the scalar quark condensate.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The results for nuclei above curium, produced in multi-nucleon transfer reactions of 〈sup〉48〈/sup〉Ca + 〈sup〉248〈/sup〉Cm at the velocity filter SHIP of GSI Darmstadt, are presented. Spontaneous fission and 〈span〉 〈span〉\( \alpha\)〈/span〉 〈/span〉-activities have been used to study the population of nuclei with lifetimes ranging from few milliseconds to several days. We observed several, relatively neutron-rich isotopes with atomic numbers 〈span〉 〈span〉\( Z \geq 98\)〈/span〉 〈/span〉; among them a weak 224 millisecond activity which we tentatively attributed to 〈sup〉260〈/sup〉No. The measured cross-sections of the observed nuclei give hope that multi-nucleon transfer reactions are a way to reach new neutron-rich heavy and superheavy nuclei, which are not accessible in other reactions. We compare our results with data from earlier experiments and discuss limitations and future perspectives of the method.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉pySecDec is a program that numerically calculates dimensionally regularized integrals. We use pySecDec to compute QCD Laplace sum-rules for pseudoscalar (〈em〉i.e.〈/em〉, 〈span〉 〈span〉\( J^{PC}=0^{-+}\)〈/span〉 〈/span〉) charmonium hybrids, and compare the results to sum-rules computed using analytic results for dimensionally regularized integrals. We find that the errors due to the use of numerical integration methods are negligible compared to the uncertainties in the sum-rules stemming from the uncertainties in the parameters of QCD, 〈em〉e.g.〈/em〉, the coupling constant, quark masses, and condensate values. Also, we demonstrate that numerical integration methods can be used to calculate finite-energy and Gaussian sum-rules in addition to Laplace sum-rules.〈/p〉

Description: 〈p〉After publication of the paper, the authors have noticed an error. Its correction is given in this erratum.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The in-medium properties of a 〈span〉 〈span〉\( \Xi N\)〈/span〉 〈/span〉 potential derived within chiral effective field theory up to next-to-leading order are investigated. The considered 〈span〉 〈span〉\( \Xi N\)〈/span〉 〈/span〉 interaction includes the coupling to other baryon-baryon channels in the strangeness 〈span〉 〈span〉\( S=-2\)〈/span〉 〈/span〉 sector ( 〈span〉 〈span〉\( \Lambda\Lambda\)〈/span〉 〈/span〉 , 〈span〉 〈span〉\( \Sigma\Sigma\)〈/span〉 〈/span〉 and is in line with available empirical constraints on the 〈span〉 〈span〉\( \Lambda\Lambda\)〈/span〉 〈/span〉〈em〉S〈/em〉 -wave scattering length and on 〈span〉 〈span〉\( \Xi N\)〈/span〉 〈/span〉 elastic and inelastic cross sections. In particular, there are no near-threshold bound states in the 〈span〉 〈span〉\( \Xi N\)〈/span〉 〈/span〉 system. A 〈em〉G〈/em〉 -matrix calculation for this interaction is performed and reveals that the single-particle potential of the 〈span〉 〈span〉\( \Xi\)〈/span〉 〈/span〉 -hyperon in nuclear matter is moderately attractive as suggested by recent experimental evidence for the existence of 〈span〉 〈span〉\( \Xi\)〈/span〉 〈/span〉 -hypernuclei.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉In this paper, we explore a new parametric class of exact solutions of the Einstein field equations (EFEs) under the Karmarkar condition for anisotropic fluids. The solutions are verified by examining different physical aspects, 〈em〉viz.〈/em〉 static stability criterion, energy conditions, stability factor, adiabatic index, causality condition, in connection to their cogency. Due to the well behaved nature of the solutions for different 〈em〉n〈/em〉 values, we develop models of objects with different masses and radii, such as PSR J1614-2230, Cen X-1, Her X-1, Vela X-1, LMC X-4 and SMC X-4 and discuss the behavior with a graphical representation of the class of solutions of the first three objects extensively.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The cross section of the 〈sup〉193〈/sup〉Ir(n, 2n)〈sup〉192〈/sup〉Ir reaction has been determined by means of the activation technique, relative to the 〈sup〉27〈/sup〉Al (n,〈span〉 〈span〉\( \alpha\)〈/span〉 〈/span〉) and 〈sup〉197〈/sup〉Au(n, 2n) reference reactions cross sections, at neutron beam energies ranging from 10 to 21 MeV. The quasi-monoenergetic neutron beams were produced at the 5.5 MV Tandem T11/25 Accelerator Laboratory of NCSR “Demokritos” via the 〈sup〉2〈/sup〉H(d, n) and 〈sup〉3〈/sup〉H(d, n) reactions. The induced 〈span〉 〈span〉\( \gamma\)〈/span〉 〈/span〉-ray activity of the irradiated target and reference foils was measured with high resolution HPGe detectors. In order to correct for the contribution of the 〈sup〉191〈/sup〉Ir(n,〈span〉 〈span〉\( \gamma\)〈/span〉 〈/span〉)〈sup〉192〈/sup〉Ir reaction, which is open to low energy parasitic neutrons, a recently developed analysis method was implemented and it is presented in great detail. Furthermore, cross section theoretical calculations were carried out using the EMPIRE and TALYS codes over a wide energy range.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉In this paper, we present an extraction of the contribution from the “〈em〉residual〈/em〉” light charged hadrons to the inclusive unidentified light charged hadron fragmentation functions (FFs) at next-to-leading (NLO) and, for the first time, at next-to-next-to-leading order (NNLO) accuracy in perturbative QCD. Considering the contributions from charged pion, kaon and (anti)proton FFs from recent NNFF1.0 analysis of charged hadron FFs, we determine the small but efficient 〈em〉residual〈/em〉 charged hadron FFs from QCD analysis of all available single inclusive unidentified charged hadron data sets in electron-positron (〈span〉 〈span〉\( e^{+} e^{-}\)〈/span〉 〈/span〉) annihilations. The zero-mass variable flavor number scheme (ZM-VFNS) has been applied to account for the heavy flavor contributions. The obtained optimum set of 〈em〉residual〈/em〉 charged hadron FFs is accompanied by the well-known Hessian technique to assess the uncertainties in the extraction of these new sets of FFs. It is shown that the 〈em〉residual〈/em〉 contributions of charged hadron FFs have a very important impact on the inclusive charged hadron FFs and substantially on the quality and the reliability of the QCD fit. Furthermore, this study shows that the 〈em〉residual〈/em〉 contributions become also sizable for the case of heavy quark FFs as well as for the 〈em〉c〈/em〉- and 〈em〉b〈/em〉-tagged cross sections.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉In this work we investigate the possible condensation of tetraneutron resonant states in the lower density neutron rich gas regions inside Neutron Stars (NSs). Using a relativistic density functional approach we characterize the system containing different hadronic species including, besides tetraneutrons, nucleons and a set of light clusters (〈sup〉3〈/sup〉He, 〈span〉 〈span〉\( \alpha\)〈/span〉 〈/span〉 particles, deuterium and tritium). 〈span〉 〈span〉\( \sigma\)〈/span〉 〈/span〉, 〈span〉 〈span〉\( \omega\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( \rho\)〈/span〉 〈/span〉 mesonic fields provide the interaction in the nuclear system. We study how the tetraneutron presence could significantly impact the nucleon pairing fractions and the distribution of baryonic charge among species. For this we assume that they can be thermodynamically produced in an equilibrated medium and scan a range of coupling strengths to the mesonic fields from prescriptions based on isospin symmetry arguments. We find that tetraneutrons may appear over a range of densities belonging to the outer NS crust carrying a sizable amount of baryonic charge thus depleting the nucleon pairing fractions.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We report properties of 〈span〉 〈span〉\( \Lambda\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( \Sigma\)〈/span〉 〈/span〉 hyperon resonances formed in 〈span〉 〈span〉\( K^-\)〈/span〉 〈/span〉 induced reactions. Special emphasis is laid on the analysis of the three-body final states 〈span〉 〈span〉\( 2\pi^{0}\Lambda\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( 2\pi^{0}\Sigma\)〈/span〉 〈/span〉 and of the quasi-two-body final states 〈span〉 〈span〉\( \pi\Lambda (1520)\)〈/span〉 〈/span〉, 〈span〉 〈span〉\( \bar{K}\Delta (1232)\)〈/span〉 〈/span〉, 〈span〉 〈span〉\( \pi\Sigma (1385)\)〈/span〉 〈/span〉, 〈span〉 〈span〉\( \bar{K}^{\ast}N\)〈/span〉 〈/span〉, and 〈span〉 〈span〉\( \omega\Lambda\)〈/span〉 〈/span〉. We give pole positions of 〈span〉 〈span〉\( \Lambda\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( \Sigma\)〈/span〉 〈/span〉 hyperon resonances and transition residues from the 〈span〉 〈span〉\( K^{-}p\)〈/span〉 〈/span〉 initial to various final states as well as Breit-Wigner masses and widths and decay branching ratios. Twenty resonances and “bumps” reported in the Review of Particle Physics are not required in our fits, evidence for five new resonances is reported. The observed mass spectrum is compared to the spectrum calculated in the Bonn quark model. Three spin doublets, six 〈span〉 〈span〉\( \Lambda\)〈/span〉 〈/span〉 hyperons, are tentatively assigned to the 〈em〉SU〈/em〉(3) singlet system.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Precision measurements of vector and tensor analyzing powers of the 〈sup〉2〈/sup〉H( 〈em〉d〈/em〉, 〈em〉dp〈/em〉)〈em〉n〈/em〉 break-up process for configurations in the vicinity of the quasi-free scattering regime with the neutron as spectator are presented. These measurements are performed with a polarized deuteron-beam with an energy of 65MeV/nucleon impinging on a liquid-deuterium target. The experiment was conducted at the AGOR facility at KVI using the BINA 4〈span〉 〈span〉\( \pi\)〈/span〉 〈/span〉-detection system. Events for which the final-state deuteron and proton are coplanar have been analyzed and the data have been sorted for various momenta of the missing neutron. In the limit of vanishing neutron momentum and at large deuteron-proton momentum transfer, the data agree well with the measured and theoretically predicted spin observables of the elastic deuteron-proton scattering process. The agreement deteriorates rapidly with increasing neutron momentum and/or decreasing momentum transfer from the deuteron beam to the outgoing proton. This study reveals the presence of a significant contribution of final-state interactions even at very small neutron momenta.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The production of selenium ion beams has been investigated at the CERN-ISOLDE facility via two different ionization methods. Whilst molecular selenium (SeCO) beams were produced at ISOLDE since the early 1990s, recent attempts at reliably reproducing these results have so far been unsuccessful. Here we report on tests of a step-wise resonance laser ionization scheme for atomic selenium using the ISOLDE Resonance Ionization Laser Ion Source (RILIS). For stable selenium an ionization efficiency of 1% was achieved. During the first on-line radioisotope production tests, a yield of 〈span〉 〈span〉\( \approx 2.4 \times 10^4\)〈/span〉 〈/span〉 ions/μC was measured for 〈sup〉71〈/sup〉Se〈sup〉+〈/sup〉, using a ZrO〈sub〉2〈/sub〉 target with an electron impact ion source. In parallel, an approach for extraction of molecular carbonyl selenide (SeCO) beams was tested. The same ion source and target material were used and a maximum yield of 〈span〉 〈span〉\( \approx 3.6\times 10^5\)〈/span〉 〈/span〉 ions/μ C of 〈sup〉71〈/sup〉SeCO〈sup〉+〈/sup〉 was measured.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Photon strength functions describing the average response of the nucleus to an electromagnetic probe are key input information in the theoretical modelling of nuclear reactions. Consequently they are important for a wide range of fields such as nuclear structure, nuclear astrophysics, medical isotope production, fission and fusion reactor technologies. They are also sources of information for widely used reaction libraries such as the IAEA Reference Input Parameter Library and evaluated data files such as EGAF. In the past two decades, the amount of reaction gamma-ray data measured to determine photon strength functions has grown rapidly. Different experimental techniques have led to discrepant results and users are faced with the dilemma of which (if any) of the divergent data to adopt. We report on a coordinated effort to compile and assess the existing experimental data on photon strength functions from the giant dipole resonance region to energies below the neutron separation energy. The assessment of the discrepant data at energies around or below the neutron separation energy has been possible only in a few cases where adequate information on the model-dependent analysis and estimation of uncertainties was available. In the giant dipole resonance region, we adopt the recommendations of the new IAEA photonuclear data library. We also present global empirical and semi-microscopic models that describe the photon strength functions in the entire energy region and reproduce reasonably well most of the experimental data. The compiled experimental photon strengths and recommended model calculations are available from the PSF database hosted at the IAEA (〈a href="http://www-nds.iaea.org/PSFdatabase"〉http://www-nds.iaea.org/PSFdatabase〈/a〉).〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉In heavy ion collisions at low energy (〈em〉E〈/em〉/〈em〉A〈/em〉 〈 10–15 MeV/nucleon) the 〈em〉N〈/em〉/〈em〉Z〈/em〉 ratio in the entrance channel is closely related to the isospin degree of freedom and can influence the reaction mechanisms and consequently the production of the fragments in the exit channel. We analyse the fragment production cross sections in the reactions 〈sup〉86〈/sup〉Kr + 〈sup〉48〈/sup〉Ca and 〈sup〉78〈/sup〉Kr + 〈sup〉40〈/sup〉Ca , at the laboratory energy of 10 MeV/nucleon. The experiment was conducted at the INFN Laboratori Nazionali del Sud in Catania, by using the 〈span〉 〈span〉\( 4\pi\)〈/span〉 〈/span〉 detector CHIMERA. For the two reactions, elastic scattering measurements are performed to extract the normalization factor used to evaluate the absolute cross sections. Velocity and energy spectra, mass and charge distributions, as well as dynamic features of reaction products, are studied. The study of the characteristics of mass and charge distributions, energy and velocity spectra of the reaction products shows mainly a relaxed component, related to fusion reaction followed by evaporation or binary decay. Nevertheless signals ascribable to a non equilibrated component are present. Structure effects are evident in the staggered shape of emitted fragments cross sections and are more pronounced in the neutron poor system. The analysis highlights clear differences for the two systems in the contributions arising from different reaction mechanisms. Besides, a study of the overall influence from the entrance channel energy is performed. Comparisons to DNS (DiNuclear System) and GEMINI++ models are reported. The data analysis indicates a slightly higher fusion-evaporation cross section and a strongly pronounced probability of fission-like processes for the neutron poor system with respect to the neutron rich one. The neutron enrichment seems thus to limit the formation of the composite system and to inhibit the fission decay channel.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We perform a calculation of the 〈span〉 〈span〉\( \tau^{-} \rightarrow \nu_{\tau} M_{1} M_{2}\)〈/span〉 〈/span〉, with 〈span〉 〈span〉\( M_{1}, M_{2}\)〈/span〉 〈/span〉 either pseudoscalar or vector mesons using the basic weak interaction and angular momentum algebra to relate the different processes. The formalism also leads to a different interpretation of the role played by 〈em〉G〈/em〉-parity in these decays. We also observe that, while 〈em〉PP〈/em〉〈em〉p〈/em〉-wave production is compatible with chiral perturbation theory and experiment, 〈em〉VP〈/em〉 and 〈em〉VV〈/em〉〈em〉p〈/em〉-wave production is clearly incompatible with experiment and we develop the formalism also in this case, producing the 〈em〉VP〈/em〉 or 〈em〉VV〈/em〉 pairs in 〈em〉s〈/em〉-wave. We compare our results with experiment and other theoretical approaches for rates and invariant mass distributions and make predictions for unmeasured decays. We show the value of these reactions, particularly if the 〈span〉 〈span〉\( M_{1} M_{2}\)〈/span〉 〈/span〉 mass distribution is measured, as a tool to learn about the meson-meson interaction and the nature of some resonances, coupling to two mesons, which are produced in such decays.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉In a fusion-evaporation reaction, nuclei are produced by evaporating light-charged particles and neutrons from the compound nucleus. Typically, a nucleus of interest is produced as a result of a part of the total cross-section and, in order to guarantee a good channel discrimination, a particle detector, like the EUCLIDES 〈span〉 〈span〉\(4\pi\)〈/span〉 〈/span〉 Si-ball array, is necessary. EUCLIDES has been quoted in more than a hundred publications resulting from many experiments performed in combination with the EUROBALL and GASP 〈span〉 〈span〉\(\gamma\)〈/span〉 〈/span〉-ray spectrometers. The present paper reports on the upgraded version of EUCLIDES, that is presently coupled to the new GALILEO 〈span〉 〈span〉\(\gamma\)〈/span〉 〈/span〉-ray spectrometer, installed at the Laboratori Nazionali di Legnaro, INFN. The design, characteristics and performance of the EUCLIDES array are presented and discussed.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Low lying states of 〈sup〉198〈/sup〉Hg have been investigated via 〈sup〉197〈/sup〉Au(〈sup〉7〈/sup〉Li,〈span〉 〈span〉\(\alpha\)〈/span〉 〈/span〉2〈em〉n〈/em〉〈span〉 〈span〉\(\gamma\)〈/span〉 〈/span〉) reaction at 〈span〉 〈span〉\( E_{\mathrm{beam}} = 33, 38\)〈/span〉 〈/span〉 MeV and the members of the 〈span〉 〈span〉\(\gamma\)〈/span〉 〈/span〉-vibrational band have been identified. Results are compared with the systematic of this mass region and found in agreement. The observed band structures have been interpreted using the theoretical framework of the microscopic triaxial projected shell model (TPSM) approach and it is shown that TPSM results are in fair agreement with the observed energies.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The primary aim of experimental nuclear astrophysics is to determine the rates of nuclear reactions taking place in stars in various astrophysical conditions. These reaction rates are an important ingredient for understanding the elemental abundance distribution in our solar system and the galaxy. The reaction rates are determined from the cross sections which need to be measured at energies as close to the astrophysically relevant ones as possible. In many cases the final nucleus of an astrophysically important reaction is radioactive which allows the cross section to be determined based on the off-line measurement of the number of produced isotopes. In general, this technique is referred to as the activation method, which often has substantial advantages over in-beam particle- or 〈span〉 〈span〉\( \gamma\)〈/span〉 〈/span〉 -detection measurements. In this paper the activation method is reviewed from the viewpoint of nuclear astrophysics. Important aspects of the activation method are given through several reaction studies for charged particle, neutron and 〈span〉 〈span〉\( \gamma\)〈/span〉 〈/span〉 -induced reactions. Various techniques for the measurement of the produced activity are detailed. As a special case of activation, the technique of Accelerator Mass Spectrometry in cross section measurements is also reviewed.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The differential cross sections of triton from the 〈sup〉11〈/sup〉B(〈span〉 〈span〉\(\alpha\)〈/span〉 〈/span〉,〈em〉t〈/em〉) reaction with transitions to the ground (0〈sup〉+〈/sup〉) and excited states of the 〈sup〉12〈/sup〉C nucleus at 〈span〉 〈span〉\( E_{x} = 4.44\)〈/span〉 〈/span〉 MeV (2〈sup〉+〈/sup〉), 7.65 MeV (0〈sup〉+〈/sup〉), 9.64 MeV (3〈sup〉-〈/sup〉) and 14.08 MeV (4〈sup〉+〈/sup〉) have been measured at an 〈span〉 〈span〉\(\alpha\)〈/span〉 〈/span〉-particles energy of 40 MeV. Analysis of the measured angular distributions was carried out in the framework of the coupled reaction channels method considering the contribution of the 〈sup〉8〈/sup〉Be cluster exchange mechanism. It is shown that the direct mechanism with proton transfer dominates at an energy of 40 MeV, and the heavy particle transfer is noticeable only at large angles. An exception is the transition to the 14.08 MeV (4〈sup〉+〈/sup〉) state, which is possible only by the transfer of the 〈sup〉8〈/sup〉Be cluster. It is established that the couplings between the excited states of 〈sup〉12〈/sup〉C, arising from the nonsphericity of the nucleus, have little effect on the 〈span〉 〈span〉\( (\alpha, t)\)〈/span〉 〈/span〉 reaction cross sections in the forward hemisphere, but strongly affect the cross sections at large angles.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Many data in the High Energy Physics are, in fact, sample means. It is shown that when this exact meaning of the data is taken into account and the most weakly bound states are removed from the hadron resonance gas, the whole spectra of pions, kaons and protons measured at midrapidity in Pb-Pb collisions at 〈span〉 〈span〉\( \sqrt{s_{NN}} = 2.76\)〈/span〉 〈/span〉 TeV can be fitted simultaneously. The invariant distributions are predicted with the help of the single-freeze-out model in the chemical equilibrium framework. The method is applied to the measurements in centrality bins of Pb-Pb collisions and gives acceptable fits for all but peripheral bins. The comparison with the results obtained in the framework of the original single-freeze-out model is also presented. Some more general, possible implications of this approach are pointed out.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉By numerically inverting the Tolman-Oppenheimer-Volkov (TOV) equation using an explicitly isospin-dependent parametric Equation of State (EOS) of dense neutron-rich nucleonic matter, a restricted EOS parameter space is established using observational constraints on the radius, maximum mass, tidal deformability and causality condition of neutron stars (NSs). The constraining band obtained for the pressure as a function of energy (baryon) density is in good agreement with that extracted recently by the LIGO+Virgo Collaborations from their improved analyses of the NS tidal deformability in GW170817. Rather robust upper and lower boundaries on nuclear symmetry energies are extracted from the observational constraints up to about twice the saturation density 〈span〉 〈span〉\(\rho_{0}\)〈/span〉 〈/span〉 of nuclear matter. More quantitatively, the symmetry energy at 〈span〉 〈span〉\(2\rho_{0}\)〈/span〉 〈/span〉 is constrained to 〈span〉 〈span〉\( E_{\mathrm{sym}}(2\rho_{0})= 46.9\pm 10.1\)〈/span〉 〈/span〉 MeV excluding many existing theoretical predictions scattered between 〈span〉 〈span〉\( E_{\mathrm{sym}}(2\rho_{0}) =15\)〈/span〉 〈/span〉 and 100 MeV. Moreover, by studying variations of the causality surface where the speed of sound equals that of light at central densities of the most massive neutron stars within the restricted EOS parameter space, the absolutely maximum mass of neutron stars is found to be 2.40 〈span〉 〈span〉\( \mathrm{M}_{\odot}\)〈/span〉 〈/span〉 approximately independent of the EOSs used. This limiting mass is consistent with findings of several recent analyses and numerical general relativity simulations about the maximum mass of the possible super-massive remanent produced in the immediate aftermath of GW170817. deformability〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We investigate relativistic quantum mechanics (RQM) for particles with arbitrary magnetic moment. We compare two well known RQM models: a) Dirac equation supplemented with an incremental Pauli term (DP); b) Klein-Gordon equations with full Pauli EM dipole moment term (KGP). We compare exact solutions to the external field cases in the limit of weak and strong (critical) fields for: i) homogeneous magnetic field, and ii) the Coulomb 〈span〉 〈span〉\( 1/r\)〈/span〉 〈/span〉-potential. For i) we consider the Landau energies and the Landau states as a function of the gyromagnetic factor (〈em〉g〈/em〉-factor). For ii) we investigate contribution to the Lamb shift and the fine structure splitting. For both we address the limit of strong binding and show that these two formulations grossly disagree. We discuss possible experiments capable of distinguishing between KGP and DP models in laboratory. We describe the impact of our considerations in the astrophysical context (magnetars). We introduce novel RQM models of magnetic moments which can be further explored.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The level density is calculated using the Barden-Cooper-Schriefer (BCS) and Lipkin-Nogami (LN) models for 〈sup〉206〈/sup〉Pb and 〈sup〉138〈/sup〉Ba nuclei and compared with the experimental data. It has been shown that the calculated level densities using both models are highly matched with the experimental data. The spin cut off factor, moment of inertia, excitation energy, and entropy were calculated using the above mentioned models. The protons in the 〈sup〉206〈/sup〉Pb nucleus occupy a closed shell and the 〈sup〉138〈/sup〉Ba nucleus has a closed neutron shell. It was revealed that the contribution of the nucleons with magic number to the mentioned thermodynamic quantities is less than that of the nucleons from open shells at low temperature.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The properties of the quantum electrodynamic (QED) vacuum in general, and of the nuclear vacuum (ground) state in particular, are determined by virtual processes implying the excitation of a photon and of an electron-positron pair in the first case and of, for example, the excitation of a collective quadrupole surface vibration and a particle-hole pair in the nuclear case. Signals of these processes can be detected in the laboratory in terms of what can be considered a nuclear analogue of Hawking radiation. An analogy which extends to other physical processes involving QED vacuum fluctuations like the Lamb shift, pair creation by 〈span〉 〈span〉\(\gamma\)〈/span〉 〈/span〉-rays, van der Waals forces and the Casimir effect, to the extent that one concentrates on the eventual outcome resulting by forcing a virtual process to become real, and not on the role of the black hole in defining the event horizon. In the nuclear case, the role of this event is taken over at a microscopic and fully quantum mechanical level, by nuclear probes (reactions) acting on virtual particles of the zero point fluctuations (ZPF) of the nuclear vacuum in a similar irreversible, no-return, fashion as the event horizon does, letting the other particle, entangled with the first one, escape to infinity, and eventually be detected. With this proviso in mind one can posit that the reactions 〈sup〉1〈/sup〉H(〈sup〉11〈/sup〉Be,〈sup〉10〈/sup〉Be(2〈sup〉+〈/sup〉;3.37MeV))〈sup〉2〈/sup〉H and 〈sup〉1〈/sup〉H(〈sup〉11〈/sup〉Li,〈sup〉9〈/sup〉Li(1/2〈sup〉-〈/sup〉;2.69MeV))〈sup〉3〈/sup〉H together with the associated 〈span〉 〈span〉\( \gamma\)〈/span〉 〈/span〉-decay processes indicate a possible nuclear analogy of Hawking radiation.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The number of nucleon (NN) scaling of the directed flow v〈sub〉1〈/sub〉 and elliptic flow ( 〈span〉 〈span〉\( v_{2}\)〈/span〉 〈/span〉 as well as the nuclear modification factor ( 〈span〉 〈span〉\( R_{cp}\)〈/span〉 〈/span〉 are tested for light nuclei which are produced in 0.4〈em〉A〈/em〉 GeV 〈sup〉197〈/sup〉Au + 〈sup〉197〈/sup〉Au collisions at different impact parameters with two different in-medium nucleon-nucleon cross sections in the framework of an isospin-dependent quantum molecular dynamics (IQMD) model. In that energy domain, the emission of light nuclei can be well described by the squeeze-out phenomenon. The results show a nice NN scaling behavior for flow parameters 〈span〉 〈span〉\( v_{1}\)〈/span〉 〈/span〉 , 〈span〉 〈span〉\( v_{2}\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( R_{cp}\)〈/span〉 〈/span〉 . These results demonstrate that the nucleon coalescence mechanism is responsible for nucleon-number scaling of above physical observables in the squeeze-out region in heavy-ion collisions at intermediate energy.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Within the relativistic mean-field framework with hadron masses and coupling constants dependent on the mean scalar field we study properties of nuclear matter at finite temperatures, baryon densities and isospin asymmetries relevant for heavy-ion collisions at laboratory energies below 〈span〉 〈span〉\( 2 A\)〈/span〉 〈/span〉 GeV. Previously constructed (KVORcut-based and MKVOR-based) models for the description of the cold hadron matter, which differ mainly by the density dependence of the nucleon effective mass and symmetry energy, are extended for finite temperatures. The baryon equation of state, which includes nucleons and 〈span〉 〈span〉\(\Delta\)〈/span〉 〈/span〉 resonances is supplemented by the contribution of the pion gas described either by the vacuum dispersion relation or with taking into account the 〈em〉s〈/em〉-wave pion-baryon interaction. Distribution of the charge between components is found. Thermodynamical characteristics on the 〈em〉T〈/em〉-〈em〉n〈/em〉 plane are considered. The energy-density and entropy-density isotherms are constructed and a dynamical trajectory of the hadron system formed in heavy-ion collisions is described. The effects of taking into account the 〈span〉 〈span〉\( \Delta\)〈/span〉 〈/span〉 isobars and the 〈em〉s〈/em〉-wave pion-nucleon interaction on pion differential cross sections, pion to proton and 〈span〉 〈span〉\( \pi^{-}/\pi^{+}\)〈/span〉 〈/span〉 ratios are studied. The liquid-gas first-order phase transition is studied within the same models in isospin-symmetric and asymmetric systems. We demonstrate that our models yield thermodynamic characteristics of the phase transition compatible with available experimental results. In addition, we discuss the scaled variance of baryon and electric charge in the phase transition region. Effect of the non-zero surface tension on spatial redistribution of the electric charge is considered for a possible application to heavy-ion collisions at low energies.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Linear density response functions for nuclear matter are calculated with separable 〈sup〉1〈/sup〉〈em〉S〈/em〉〈sub〉0〈/sub〉 and 〈sup〉3〈/sup〉〈em〉S〈/em〉〈sub〉1〈/sub〉 2-nucleon interactions obtained from experimental phase-shifts by inverse scattering techniques. It has been shown that results of nuclear matter binding energy Brueckner calculations with these potentials agree closely with those using realistic Bonn interactions. It has also been shown that low-momentum versions give binding energies (nearly) independent of momentum cut-offs 〈span〉 〈span〉\(\Lambda \geq \sim 2\)〈/span〉 〈/span〉 fm〈sup〉-1〈/sup〉. Shown here is that the 〈span〉 〈span〉\(\Lambda = 2\)〈/span〉 〈/span〉 rank-one version of the separable interaction (for the S-states) yields a near agreement between a second-order and an all-order (Brueckner) binding energy calculation. Second order calculations of response functions are then made with this version using a method that Kwong and Bonitz used for the Coulomb gas. It is based on time-evolving two-time Green’s functions by Kadanoff-Baym (KB) equations. The effect of correlations, going beyond the conventional HF+RPA method, is included by “dressing” the Green’s function propagators with time-dependent complex self-energies in addition to the real HF-field. It would be of interest to see if the calculated response is also, like the binding energy, independent of cut-offs 〈em〉larger〈/em〉 than 〈span〉 〈span〉\(\sim 2\)〈/span〉 〈/span〉 fm〈sup〉-1〈/sup〉. That would require using separable potentials of a higher rank, not accommodated by the present computer program. Some results with a 1.5 fm〈sup〉-1〈/sup〉 cut-off are however also shown below together with those with a 2.0 fm〈sup〉-1〈/sup〉 cut-off. The KB-equations are time-evolved until the nuclear medium is fully correlated. The time-dependent density response to an external perturbation is then registered and Fourier transformed to obtain energy-dependent density response functions. Most previous calculations have been made with in-medium effective (〈em〉e.g.〈/em〉, Gogny or Skyrme) interactions. The medium dependence is in the present calculations contained in the second-order terms.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The 〈em〉Semimicroscopic Algebraic Cluster Model〈/em〉 (SACM) is applied to 〈sup〉16〈/sup〉O, assumed to consist of a system of four 〈span〉 〈span〉\(\alpha\)〈/span〉 〈/span〉-clusters. For the 4-〈span〉 〈span〉\(\alpha\)〈/span〉 〈/span〉 cluster system we take the model space already obtained in the past, which observes the 〈em〉Pauli Exclusion Principle〈/em〉 (PEP) and is symmetric under permutation of the 〈span〉 〈span〉\(4\alpha\)〈/span〉 〈/span〉-particles. A phenomenological Hamiltonian is used. The spectrum and transition values are determined. One of the main objectives is to test the importance of the 〈em〉Pauli Exclusion Principle〈/em〉 (PEP), comparing the results with the 〈em〉Algebraic Cluster Model〈/em〉 (ACM), which does not include the PEP, and claims that for the ground state the 〈sup〉16〈/sup〉O shows evidence of a tetrahedral structure which can be explained easily by symmetry arguments. We show that the PEP is very important and cannot be neglected, otherwise it leads to a wrong interpretation of the band structure and to too many states at low energy, especially to an accumulation of parity doublets.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We revisit the problem of the production of light atomic nuclei in ultrarelativistic heavy-ion collisions. While their production systematics is well produced by hadro-chemical freezeout at temperatures near the QCD pseudo-critical temperature, their small binding energies of a few MeV per nucleon suggest that they cannot survive as bound states under these conditions. Here, we adopt the concept of effective chemical potentials in the hadronic evolution from chemical to thermal freezeout (at typically 〈span〉 〈span〉\( T_{\mathrm{fo}} \simeq 100\)〈/span〉 〈/span〉 MeV), which, despite frequent elastic rescatterings in hadronic matter, conserves the effective numbers of particles which are stable under strong interactions, most notably pions, kaons and nucleons. It turns out that the large chemical potentials that build up for antibaryons result in thermal abundances of light nuclei and antinuclei, formed at thermal freezeout, which essentially agree with the ones evaluated at chemical freezeout. Together with their transverse-momentum spectra, which also indicate a kinetic freezeout near 〈span〉 〈span〉\( T_{\mathrm{fo}}\)〈/span〉 〈/span〉 , this provides a natural explanation for their production systematics without postulating their survival at high temperatures.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉A qualitative discussion on the range of the potentials as they result from the phenomenological meson-exchange picture and from lattice simulations by the HAL QCD Collaboration is presented. For the former pion- and/or 〈span〉 〈span〉\( \eta\)〈/span〉 〈/span〉-meson exchange are considered together with the scalar-isoscalar component of correlated 〈span〉 〈span〉\(\pi\pi/K \bar{K}\)〈/span〉 〈/span〉 exchange. It is observed that the intuitive expectation for the behavior of the baryon-baryon potentials for large separations, associated with the exchange of one and/or two pions, does not always match with the potentials extracted from the lattice simulations. Only in cases where pion exchange provides the longest ranged contribution, like in the 〈span〉 〈span〉\( \Xi N\)〈/span〉 〈/span〉 system, a reasonable qualitative agreement between the phenomenological and the lattice QCD potentials is found for baryon-baryon separations of 〈span〉 〈span〉\( r \gtrsim 1\)〈/span〉 〈/span〉 fm. For the 〈span〉 〈span〉\( \Omega N\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( \Omega\Omega\)〈/span〉 〈/span〉 interactions where isospin conservation rules out one-pion exchange a large mismatch is observed, with the potentials by the HAL QCD Collaboration being much longer ranged and much stronger at large distances as compared to the phenomenological expectation. This casts some doubts on the applicability of using these potentials in few- or many-body systems.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉An analytical solution of the QCD evolution equations for the singlet and gluon distribution is presented. We decouple DGLAP evolution equations into the initial conditions by using a Laplace transform method at N〈sup〉n〈/sup〉LO analysis. The relationship between the nonlinear behavior and color dipole model is considered based on an effective exponent behavior at low 〈em〉x〈/em〉 values. We obtain the effective exponent at NLO analysis from the decoupled behavior of the distribution functions. The proton structure function compared with HERA data from the inclusive structure function 〈span〉 〈span〉\( F_{2}(x,Q^{2})\)〈/span〉 〈/span〉 for 〈span〉 〈span〉\( x \leq 10^{-2}\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( 5 \leq Q^{2} \leq 250\)〈/span〉 〈/span〉 GeV〈sup〉2〈/sup〉.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We evaluate the two-photon exchange corrections to the Lamb shift and hyperfine splitting of S states in electronic hydrogen relying on modern experimental data and present the two-photon exchange on a neutron inside the electronic and muonic atoms. These results are relevant for the precise extraction of the isotope shift as well as in the analysis of the ground state hyperfine splitting in usual and muonic hydrogen.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The first detection of gravitational waves from a neutron star-neutron star merger, GW170817, has opened up a new avenue for constraining the ultradense-matter equation of state (EOS). The deviation of the observed waveform from a point-particle waveform is a sensitive probe of the EOS controlling the merging neutron stars’ structure. In this topical review, I discuss the various constraints that have been made on the EOS in the year following the discovery of GW170817. In particular, I review the surprising relationship that has emerged between the effective tidal deformability of the binary system and the neutron star radius. I also report new results that make use of this relationship, finding that the radius inferred from GW170817 lies between 9.8 and 13.2km at 90% confidence, with distinct likelihood peaks at 10.8 and 12.3km. I compare these radii, as well as those inferred in the literature, to X-ray measurements of the neutron star radius. I also summarize the various maximum mass constraints, which point towards a maximum mass 〈span〉 〈span〉\( \lesssim 2.3 M_{\odot}\)〈/span〉 〈/span〉, depending on the fate of the remnant, and which can be used to additionally constrain the high-density EOS. I review the constraints on the EOS that have been performed directly, through Bayesian inference schemes. Finally, I comment on the importance of disentangling thermal effects in future EOS constraints from neutron star mergers.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We argue that the two-particle momentum correlation functions of high-multiplicity 〈span〉 〈span〉\( p+p\)〈/span〉 〈/span〉 collisions at the LHC provide a signal for a ground state structure of a quasi equilibrium state of the longitudinally boost-invariant expanding quantum field which lies in the future light cone of a collision. The physical picture is that pions are produced by the expanding quantum emitter with two different scales approximately attributed to the expanding ideal gas in local equilibrium state and ground-state condensate. Specifically, we show that the effect of suppressing the two-particle Bose-Einstein momentum correlation functions increases with increasing transverse momentum of a like-sign pion pair due to different momentum dependence of the corresponding particle emission regions.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Proper understanding of the stellar nucleosynthesis processes requires information on a variety of capture reaction cross sections. Since these cross sections are typically very low, they require efficient measurement techniques. The High Efficiency Total Absorption Spectrometer (HECTOR) was designed to measure capture cross sections relevant for astrophysical processes. HECTOR is a 〈span〉 〈span〉\( \gamma\)〈/span〉 〈/span〉 -summing detector comprised of 16 separate NaI(Tl) segments. The detector design is presented, as well as a detailed study of the detector's summing efficiency and analysis procedure. The results of the commissioning of HECTOR are presented. The resonance strengths of the well-known resonances in the 〈sup〉27〈/sup〉Al 〈span〉 〈span〉\( (\mathrm{p},\gamma)\)〈/span〉 〈/span〉〈sup〉28〈/sup〉Si reaction measured with HECTOR are compared with the literature values.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Hard exclusive electroproduction of kaons as well as the kaon-induced exclusive Drell-Yan process are investigated within the handbag approach which is based on factorization in hard subprocesses and soft generalized parton distributions (GPDs). The kaon-hyperon transition GPDs occurring here are related to the proton GPDs by flavor symmetry. The latter are taken from analyses of pion electroproduction. Like in hard processes involving pions the transversity GPDs play an important role in the processes of interest --the transverse cross sections are larger than (or, for the Drell-Yan process, about equal to) the longitudinal ones. The evolution of the transversity GPDs is taken into account for the first time but, as the analysis reveals, it is a minor effect in the range of photon virtualities of interest. The predictions for the cross sections agree fairly well with the sparse available electroproduction data.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The universal properties of charged particles are modified by the presence of a long-range Coulomb interaction. We investigate the modification of Efimov universality as a function of the Coulomb strength using the Gaussian Expansion Method. The resonant short-range interaction is described by Gaussian potentials to which a Coulomb potential is added. We calculate binding energies and root mean square radii for the three- and four-body systems of charged particles and present our results in a generalised Efimov plot. We find that universal features can still be discerned for weak Coulomb interaction, but break down for strong Coulomb interaction. The maximum root mean square radius of the system decreases as the strength of the Coulomb interaction is increased and the probability distributions of the states become more concentrated inside the Coulomb barrier. As an example, we apply our universal model to nuclei with an 〈span〉 〈span〉\( \alpha\)〈/span〉 〈/span〉 cluster substructure. Our results point to strong non-universal contributions in that sector.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉A simple model of a trapped ion cloud cooled by collisions in a buffer gas in a Paul trap is presented. It is based on the customary decomposition of the ion motion in micro- and macro- (or secular) motions and a statistical treatment of hard-sphere collisions and ion trajectories. The model also relies on the evidence that the effective trapping area in real Paul traps is limited to a certain radius, where the harmonics of the potential of order 〈span〉 〈span〉\(〉 2\)〈/span〉 〈/span〉 become non negligible. The model yields analytical formulae for the properties of the ion cloud and equilibration times, which are in good agreement for a wide range of parameters with the results of a numerical simulation, whose reliability has been verified. When the confining potential is efficient enough to suppress evaporation from the trap, the model yields an effective temperature for the ions 〈span〉 〈span〉\(T_{eff}=2T/(1-\frac{m_{g}}{m})\)〈/span〉 〈/span〉, where 〈em〉T〈/em〉 is the temperature of the buffer gas, 〈em〉m〈/em〉 and 〈span〉 〈span〉\(m_{g}\)〈/span〉 〈/span〉 are the masses of the ions and gas molecules, respectively. The so-called Radio Frequency (RF) heating effect, responsible for 〈span〉 〈span〉\( T_{eff} 〉 T\)〈/span〉 〈/span〉, is interpreted in light of the model as the result of an incomplete cooling of the ion motion, limited to the macromotion, while the net effect of the micromotion is to double the average ion kinetic energy for 〈span〉 〈span〉\(\frac{m}{m_{g}}\gg 1\)〈/span〉 〈/span〉. For 〈span〉 〈span〉\( \frac{m}{m_{g}} \le 1\)〈/span〉 〈/span〉, the incomplete cooling is not sufficient to overcome the thermal agitation of the cloud to which the micromotion participates; the ions are therefore led out of the trap. When a thermal equilibrium is found, the dimensions of the cloud are shown to be proportional to the square root of the effective temperature: 〈span〉 〈span〉\(\sigma_{x}=\sigma_{y}=\sigma_{r}=2\sigma_{z} \propto\sqrt{T_{eff}}\)〈/span〉 〈/span〉. In the frame of the model, the number of collisions required for the complete cooling of the ion cloud is simply approximated by 〈span〉 〈span〉\(\frac{m}{\mu}\cdot 3.5\)〈/span〉 〈/span〉, where μ is the reduced mass of the system. When the confining potential does not prevent evaporation from the trap, an approximate formula is derived for the evaporation rate that primarily depends on the ratio of the maximal energies of ions that can be trapped to the ion thermal energies. The comparison of the characteristic times of both processes permits to predict if the ion cloud will reach a thermal equilibrium before being evaporated.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The performance of the Pulse-Shape Analysis (PSA) in AGATA HPGe detectors was investigated and improved employing a 〈span〉 〈span〉\(\gamma\)〈/span〉 〈/span〉-ray source measurement based on 〈span〉 〈span〉\( e^{+}e^{-}\)〈/span〉 〈/span〉 annihilation radiation after decays of 〈sup〉22〈/sup〉Na by 〈span〉 〈span〉\( \beta^{+}\)〈/span〉 〈/span〉 decay. The first interaction positions of the two 511keV 〈span〉 〈span〉\(\gamma\)〈/span〉 〈/span〉 rays were determined and the connecting line of these two positions was compared to the known source position as a measure for the PSA performance. The position resolution and its dependence on the PSA parameters were investigated by varying most relevant input quantities: the charge carrier mobility of the holes, the response of the employed measuring electronics especially the preamplifier rise time. The relative statistical weight of charge signals and transient signals was scrutinized. The optimal distance metric of the grid-search algorithm and its impact on the position resolution were determined.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉On the brink of the phase transition from spherical to deformed Zr isotopes, 〈sup〉96〈/sup〉Zr shows a co-existence of low-lying level structures with different degrees of quadrupole collectivity. Experimental data are available, but a coherent description of the measured properties is yet missing. This paper analyses available data and critically compiles the information relevant for the interpretation of the quadrupole-collective structure of 〈sup〉96〈/sup〉Zr .〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉In this paper, we investigated the spectroscopy of heavy tetraquarks through a relativistic diquark-antidiquark model. To this aim, the two-bosonic Klein-Gordon equation in the presence of vector Coulombic-like and scalar linear potentials is solved numerically to calculate the average masses of heavy tetraquarks in the ground and excited states. Incorporating the spin-dependent interactions removes the degeneracy of the states and results in the exact masses of charm- and bottom-containing tetraquarks and throughly the predictions for the masses of bottom and charm tetraquark candidates are given.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Excited 〈em〉B〈/em〉-mesons have been observed by the D0, CDF, LHCb and CMS experiments. We use the predictions of the relativized quark model to make quark model spectroscopic assignments for these states. We identify the 〈span〉 〈span〉\(B_{2}^{\ast} (5747)\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\(B_{1} (5721)\)〈/span〉 〈/span〉 as the 〈span〉 〈span〉\(B_{2}^{\ast} [1^{3}P_{2}]\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\(B_{1}[1P_{1}]\)〈/span〉 〈/span〉 states and the 〈span〉 〈span〉\( B_{s2}^{\ast}(5840)\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( B_{s1}(5830)\)〈/span〉 〈/span〉 as the 〈span〉 〈span〉\( B_{s2}^{\ast}[1^{3}P_{2}]\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( B_{s1}[1P_1]\)〈/span〉 〈/span〉 states. More information is needed to identify the 〈span〉 〈span〉\( B_{J}(5970)\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\( B_{J}(5840)\)〈/span〉 〈/span〉 states and we suggest a number of measurements to make this identification: the determination of their 〈span〉 〈span〉\( J^{P}\)〈/span〉 〈/span〉 quantum numbers and either confirming or ruling out their decays to the 〈span〉 〈span〉\( B\pi\)〈/span〉 〈/span〉 final state. With the current information available we believe it most likely that the 〈span〉 〈span〉\( B_{J}(5970)\)〈/span〉 〈/span〉 is the 〈span〉 〈span〉\( B^{\ast}[2^{3}S_{1}]\)〈/span〉 〈/span〉 state, with the 〈span〉 〈span〉\( B_{J}(5840)\)〈/span〉 〈/span〉 needing confirmation.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Using our analytical expressions that well model the lattice simulations of the gluonic excitations, we use the extended quark potential model to study the effects of orbital and radial excitations on the masses and sizes of conventional and hybrid 〈span〉 〈span〉\( B_c\)〈/span〉 〈/span〉 mesons. A non relativistic formalism is used to numerically calculate the wave functions using the shooting method; this also allows us to calculate the 〈em〉E〈/em〉1 , 〈em〉M〈/em〉1 radiative partial widths for conventional meson to meson and hybrid to hybrid transitions. We incorporate spin mixing and compare our calculated spectrum and decay widths with the available experimental 〈span〉 〈span〉\( B_c\)〈/span〉 〈/span〉 masses and the theoretically predicted spectra and decay widths by other groups. Our results can help consider both conventional and hybrid quantum numbers for 〈span〉 〈span〉\( B_c\)〈/span〉 〈/span〉 mesons as experimental results become available.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We investigate the possible deuteron-like molecules composed of a pair of charmed spin-〈span〉 〈span〉\(\frac{3}{2}\)〈/span〉 〈/span〉 baryons, or one charmed baryon and one charmed antibaryon within the one-boson-exchange (OBE) model. For the spin singlet and triplet systems, we consider the couple channel effect between systems with different orbital angular momentum. Most of the systems have binding solutions. The couple channel effect plays a significant role in the formation of some loosely bound states. The possible molecular states of 〈span〉 〈span〉\(\Omega_{c}^{\ast}\Omega_{c}^{\ast}\)〈/span〉 〈/span〉 might be stable once produced.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉This article overviews recent developments and achievements on decay spectroscopic studies at the Radioactive-Isotope Beam Factory (RIBF) in RIKEN Nishina Center, which has come online in 2007 as the first 3rd-generation in-flight separator facility. The research territory on the chart of nuclides has been dramatically expanded both towards the proton-rich and neutron-rich frontiers with the advent of RIBF. Taking advantage of the world’s currently strongest RI beams, in conjunction with new experimental techniques and state-of-the-art detector systems, more than 400 species of rare isotopes have been explored in experimental programs dedicated to radioactive-decay measurements performed in the last decade. Some selected topics are introduced in this review. Excited levels investigated by 〈span〉 〈span〉\(\gamma\)〈/span〉 〈/span〉-ray measurements following 〈span〉 〈span〉\(\beta\)〈/span〉 〈/span〉 decay have provided significant information on the evolution of shell structures and nuclear shapes, and thus serve as a stringent benchmark for testing microscopic and macroscopic nuclear model calculations. Systematic studies of 〈span〉 〈span〉\( \beta\)〈/span〉 〈/span〉-decay half-lives of very neutron-rich nuclei have an enormous impact on a better understanding of explosive nucleosynthesis in the rapid neutron-capture (〈em〉r〈/em〉) process. On the proton-rich side of the 〈span〉 〈span〉\( \beta\)〈/span〉 〈/span〉-stability line, new proton emitters have been identified, allowing an exploration of atomic nuclei beyond the proton drip line. New results obtained in a series of decay experiments include various types of nuclear isomers, for example, seniority, spin-trap, shape, and 〈em〉K〈/em〉 isomers. The identification and characterization of such exotic isomers have revealed the underlying single-particle orbits and nucleon-nucleon correlations, as well as the change of nuclear shape and spin orientation. These new results will offer further insight into exotic nuclei and contribute to the development of new theories of nuclear structure and nucleosynthesis. In this review article, some of the ongoing research projects and future prospects for decay studies at RIBF are also presented.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We study the imaginary parts of the isoscalar electromagnetic and isovector axial form factors of the nucleon close to the 〈span〉 〈span〉\(3\pi\)〈/span〉 〈/span〉-threshold in covariant baryon chiral perturbation theory. At the two-loop level, the contributions arising from leading and next-to-leading order chiral 〈span〉 〈span〉\(\pi N\)〈/span〉 〈/span〉-vertices, as well as pion-induced excitations of virtual 〈span〉 〈span〉\(\Delta (1232)\)〈/span〉 〈/span〉-isobars, are calculated. It is found that the heavy baryon treatment overestimates substantially these 〈span〉 〈span〉\( 3\pi\)〈/span〉 〈/span〉-continua. From a phenomenological analysis, that includes the narrow 〈span〉 〈span〉\( \omega(783)\)〈/span〉 〈/span〉-resonance or the broad 〈span〉 〈span〉\( a_1\)〈/span〉 〈/span〉-resonance, one can recognize small windows near threshold, where chiral 〈span〉 〈span〉\( 3\pi\)〈/span〉 〈/span〉-dynamics prevails. However, in the case of the isoscalar electromagnetic form factors 〈span〉 〈span〉\( G_{E,M}^{s}(t)\)〈/span〉 〈/span〉, the radiative correction provided by the 〈span〉 〈span〉\( \pi^{0}\gamma\)〈/span〉 〈/span〉-intermediate state turns out to be of similar size.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The superheavy isotope 〈sup〉258〈/sup〉Db was produced in the 〈sup〉209〈/sup〉Bi(〈sup〉50〈/sup〉Ti, 1n)〈sup〉258〈/sup〉Db reaction at GSI, Germany. A detailed 〈span〉 〈span〉\( \alpha\)〈/span〉 〈/span〉-spectroscopy study of this isotope and its 〈span〉 〈span〉\( \alpha\)〈/span〉 〈/span〉-decay daughter products was performed. Two long-lived 〈span〉 〈span〉\( \alpha\)〈/span〉 〈/span〉-decaying states in 〈sup〉258〈/sup〉Db are observed. A spin-parity of 〈span〉 〈span〉\( 0^{-}\)〈/span〉 〈/span〉 is tentatively assigned to the ground state for which a half-life of 〈span〉 〈span〉\( 2.17 \pm 0.36\)〈/span〉 〈/span〉 s is determined. Spins and parities of either 〈span〉 〈span〉\( 5^{+}\)〈/span〉 〈/span〉 or 〈span〉 〈span〉\( 10^{-}\)〈/span〉 〈/span〉 are proposed for the isomeric state found at an excitation energy of 51 keV with a half-life of 〈span〉 〈span〉\( 4.41 \pm 0.21\)〈/span〉 〈/span〉 s. The 〈span〉 〈span〉\( \alpha\)〈/span〉 〈/span〉 -decay daughter isotope 〈sup〉254〈/sup〉Lr displays a similar behavior. A half-life of 〈span〉 〈span〉\( 11.9 \pm 0.9\)〈/span〉 〈/span〉 s is determined for the 〈sup〉254〈/sup〉Lr ground state which is tentatively assigned a spin-parity of 〈span〉 〈span〉\( 4^{+}\)〈/span〉 〈/span〉. The isomeric level of this isotope placed at 108 keV with a half-life of 〈span〉 〈span〉\( 20.3 \pm 4.2\)〈/span〉 〈/span〉 s is tentatively assigned a spin-parity of 〈span〉 〈span〉\( 1^{-}\)〈/span〉 〈/span〉. Two long-lived 〈span〉 〈span〉\( \alpha\)〈/span〉 〈/span〉-decaying states are observed in the granddaughter isotope 〈sup〉250〈/sup〉Md . The ground state has a half-life of 〈span〉 〈span〉\( 59.5 \pm 9.1\)〈/span〉 〈/span〉 s. A half-life of 〈span〉 〈span〉\( 42.4 \pm 4.5\)〈/span〉 〈/span〉 s is measured for the isomeric state positioned at an excitation energy of 123 keV. Partial, tentative level schemes for 〈sup〉254〈/sup〉Lr, 〈sup〉250〈/sup〉Md and 〈sup〉246〈/sup〉Es are proposed based on the 〈span〉 〈span〉\( \alpha\)〈/span〉 〈/span〉-〈span〉 〈span〉\( \gamma\)〈/span〉 〈/span〉 coincidences.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Neutrons play a dominant role in the stellar nucleosynthesis of heavy elements and the quest for accurate experimental determinations of neutron-induced reaction cross sections becomes more stringent with the refinement of nuclear and astrophysical models. We review here an experimental nuclear-astrophysics program using a high-intensity neutron source based on the 〈sup〉7〈/sup〉Li(〈em〉p〈/em〉, 〈em〉n〈/em〉)〈sup〉7〈/sup〉Be reaction with a Liquid-Lithium Target (LiLiT) at the Soreq Applied Research Accelerator Facility (SARAF) Phase I. The quasi-Maxwellian neutron spectrum with effective thermal energy 〈span〉 〈span〉\( kT \approx 30\)〈/span〉 〈/span〉 keV, characteristic of the thick-target 〈sup〉7〈/sup〉Li(〈em〉p〈/em〉, 〈em〉n〈/em〉) yield at proton energy 〈span〉 〈span〉\( E_p \approx 1.92\)〈/span〉 〈/span〉 MeV close to its neutron threshold, is well suited for laboratory measurements of neutron capture reactions along the astrophysical 〈em〉s〈/em〉 -process path. The high-intensity proton beam (in the mA range) of SARAF and the high power (few kW) dissipation of LiLiT result in the most intense source of neutrons available today at stellar-like energies. The principle, design and properties of the LiLiT device and recent measurements of Maxwellian Averaged Cross Sections (MACS) based on activation of targets of astrophysical interest are described. Decay counting or atom counting methods (accelerator mass spectrometry, atom-trap trace analysis) are used for the detection of short-lived or long-lived activation products, respectively. In a different realm of applications, the 〈sup〉7〈/sup〉Li(〈em〉p〈/em〉, 〈em〉n〈/em〉) reaction is a leading candidate as an accelerator-based neutron source for Boron Neutron Capture Therapy (BNCT). The high neutron yield achievable from a liquid-lithium target, its sustainability of operation under kW-power incident beams and the recent availability of small-size high-intensity accelerators are compatible with a hospital-based clinical facility. An effort towards the characterization and realization of a liquid-lithium target for BNCT is reviewed. Perspectives of pending and future developments towards SARAF Phase II, based on a 40MeV, 5mA CW proton/deuteron superconducting linear accelerator, are summarized.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉In nucleus-nucleus collisions, new particles are produced mainly through strong interactions among the constituents of the QCD medium. The search of a unified phenomenological model to understand this production mechanism is one of the main motivation behind the heavy ion experiments. A vast variety of data coming from nucleus-nucleus collision experiments put a stringent constraint on the particle production models. A unified and proper model must satisfy the various data regarding pseudorapidity distributions, transverse energy density distributions, transverse momentum distributions with respect to control parameters in different types of collisions at various energies simultaneously. Recently we proposed a new version of wounded quark model (WQM) which actually satisfies many points of this criteria. However, these kind of static initial model conditions have problem in calculating the transverse momentum distributions of charged hadrons. In this article, we have used the important ingredients of WQM like number of wounded quarks and number of quark-quark collisions to fit the transverse momentum spectra of charged hadrons. Based on the assumption of different mechanisms at different regions, 〈em〉i.e.〈/em〉 different mechanisms for soft 〈span〉 〈span〉\( p_{T}\)〈/span〉 〈/span〉 and hard momentum part, we have proposed a parameterization made of two functions to calculate the transverse momentum spectra in different collisions at different energies ranging from higher RHIC to LHC. We hope that this study along with our recent work on WQM will become a more suitable choice as unified model for particle production in strong interaction, instead of wounded nucleon model.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉We report on the development and characterization of the first radioactive boron beams produced by the isotope mass separation online (ISOL) technique at CERN-ISOLDE. Despite the long history of the ISOL technique which exploits thick targets, boron beams have up to now not been available. This is due to the low volatility of elemental boron and its high chemical reactivity which make the definition of an appropriate production target unit difficult. In addition, the short half-lives of all boron radioisotopes complicate tracer release studies. We report here on dedicated offline release studies by neutron capture and alpha detection done with implanted 〈sup〉10〈/sup〉B in prospective target materials, as well as molecule formation and ionization tests, which suggested the use of multiwalled carbon nanotubes (CNT) as target material and injection of sulfur hexafluoride SF〈sub〉6〈/sub〉 to promote volatile boron fluoride formation. Two target units equipped with an arc discharge electron impact ion source VADIS coupled to a water cooled transfer line to retain non-volatile elements and molecules were subsequently tested online. The measured yield of these first 〈sup〉8〈/sup〉B ISOL beams increases in the series 〈span〉 〈span〉\({}^{8}\mathrm{BF}_{3} 〈 {}^{8}\mathrm{BF} 〈 {}^{8}\mathrm{B} 〈 {}^{8}\mathrm{BF}_{2}\)〈/span〉 〈/span〉, reaching a maximum yield of 〈span〉 〈span〉\( 6.4 \times 10^{4}\)〈/span〉 〈/span〉〈sup〉8〈/sup〉BF〈sub〉2〈/sub〉〈sup〉+〈/sup〉 ions per μC of protons.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉A good knowledge of the radiative capture cross section of 〈sup〉242〈/sup〉Pu is required for innovative nuclear reactor studies, especially for MoX fuel reactors. However, the experimental data available show discrepancies in the energy regions of interest: the thermal point and the keV region. Previous experimental results of the thermal cross section deviate from each other by 20% and these discrepancies are reflected also in the evaluated libraries, each of them giving more credit to different data sets. A recent measurement by Genreith 〈em〉et al.〈/em〉 did not succeed to solve the existing discrepancy due to the large uncertainties and correction factors in the analysis. This work presents a new measurement of the thermal capture cross section of 〈sup〉242〈/sup〉Pu carried out in the Budapest Research Reactor using the same thin targets of a previous measurement at n_TOF-EAR1, each containing 30mg of 99.995% pure 〈sup〉242〈/sup〉Pu . The combined analysis of the full prompt 〈span〉 〈span〉\( \gamma\)〈/span〉 〈/span〉-ray spectrum and the 〈sup〉243〈/sup〉Pu decay has led to three compatible values for the thermal cross section. Their average value, 18.9(9)b, has an improved accuracy compared to recent measurements. Leaving aside the activation value of Genreith using an outdated intensity value for the 84 keV decay line of 〈sup〉243〈/sup〉Pu , our average result is in very good agreement with the JEFF-3.2 evaluation and all the previous measurements, with the exception of the highest value 22.5(11)b reported by Marie 〈em〉et al.〈/em〉, which has a strong influence in the ENDF evaluation.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The coherent meson scattering off heavy nuclei with the production of two particles in the final state is investigated. We obtain the form factors for the direct production of the final state and through intermediate particles, unstable ones that can decay inside the nucleus and virtual ones. The cases of scattering both in the Coulomb and in the strong field of the nucleus are considered. This work is stimulated by an experimental study of the chiral anomaly in a beam of charged kaons in the OKA facility.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The time-dependent density-matrix theory (TDDM) where the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy for reduced density matrices is truncated by approximating a three-body density matrix with one-body and two-body density matrices is applied to the Lipkin model. It is shown that in the large 〈em〉N〈/em〉 limit the ground state in TDDM approaches the exact solution. Various truncation schemes for the three-body density matrix are also tested for an extended three-level Lipkin model.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The 〈span〉 〈span〉\(\rho\)〈/span〉 〈/span〉-meson spectral function in hot and dense asymmetric nuclear matter (number densities of proton and neutron different) is evaluated in an effective chiral 〈em〉SU〈/em〉(3) model within the mean field approximation (MFA). The dependence of the vector meson masses on density and temperature, their variation with the asymmetry parameter, the form of the spectral function when the 〈span〉 〈span〉\( p \longleftrightarrow n\)〈/span〉 〈/span〉 symmetry is broken are studied. One can observe a clear splitting of the longitudinal and the transverse modes among the 〈span〉 〈span〉\(\rho\)〈/span〉 〈/span〉 isospin multiplets. The role of a running tensor coupling on the spectral function is also studied.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉Cross section measurements of (〈span〉 〈span〉\(p, \gamma\)〈/span〉 〈/span〉) reactions on the Mo isotopes have been performed at beam energies from 2 to 6.2 MeV that are relevant to the 〈em〉p〈/em〉-process. Partial cross sections and isomeric ratios were also determined for the 〈sup〉92〈/sup〉Mo case. Astrophysical S factors as well as reaction rates were derived from the experimental cross sections. Statistical model calculations were performed using the latest version (1.9) of the statistical model code TALYS and were compared with the new data. An overall good agreement between theory and experiment was found. In addition, the effect of different combinations of the nuclear input parameters entering the stellar reaction-rate calculations was investigated. It was found that, for certain combinations of optical-model potentials, nuclear level densities and 〈span〉 〈span〉\(\gamma\)〈/span〉 〈/span〉-ray strength functions, the nuclear uncertainties propagated through the Hauser-Feshbach calculations are less than a factor of 2 which is well below the average discrepancies of the calculated 〈em〉p〈/em〉-nuclei abundances and the observations.〈/p〉

Description: 〈h3〉Abstract.〈/h3〉 〈p〉The study of nuclear resonances in the intermediate energy regime requires accurate modeling of the experimental physics background. The cross sections in the GEANT4 toolkit do not adequately treat meson photo-production. The purpose of this study is to compare experimental data and theoretical models implemented in version 9.6.p02 of the GEANT4 Monte Carlo simulation toolkit for the exclusive and differential cross sections of 〈span〉 〈span〉\( \pi^0\)〈/span〉 〈/span〉 photo-production. Two models were studied: the Chiral Invariant Phase Space (CHIPS) and Bertini Cascade (BERT). The cross section data from the models were compared to the experimental data from the CEBAF Large Acceptance Spectrometer (CLAS) of Jefferson Lab and the phenomenological Scattering Analysis Interactive Dial-in (SAID) model. Relativistic Breit-Wigner fits were used to compare the 〈span〉 〈span〉\(\Delta(1232)\)〈/span〉 〈/span〉, 〈span〉 〈span〉\(N(1520)\)〈/span〉 〈/span〉, 〈span〉 〈span〉\(N(1650)\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\(N(1875)\)〈/span〉 〈/span〉 resonances from SAID, CLAS and CHIPS, giving agreements to within 3% for the mass of each resonance. The limited tabulated data set of BERT does not allow for an accurate description of the energy distribution, even following its improvement in version 10p02. The angular distributions of the cross sections show significant differences between CHIPS and both CLAS and SAID data, the latter being the most accurate model to describe the 〈span〉 〈span〉\(\gamma p\rightarrow p\pi^0\)〈/span〉 〈/span〉 exclusive cross section. The physics in CHIPS appears to be correct but it needs further development for the individual resonances contributions that could be useful since it is also the only model able to treat electromagnetically induced meson production for 〈span〉 〈span〉\(A 〉 1\)〈/span〉 〈/span〉.〈/p〉