We investigate the influence of nucleon superfluidity on the neutrino emissivity of nonequilibrium $\beta$ processes. Calculations of the reduction factors for direct and modified Urca processes with three types of nucleon superfluidity in $\mathit{npe}$ matter are performed. The numerical results are given because the analytical solution is impossible. We find that the superfluid influence is closely related to the chemical departure from $\beta$ equilibrium. For a small chemical departure, the superfluid reduction factor depends almost only on the gap and is hardly affected by the departure, while for a large enough departure, it rapidly enhances neutrino emissivity. The onset of “enchanced” emission has some corresponding thresholds that seem to be linked to the ratio of the energy gap to the chemical departure.

The role of transfer channels or neck formation in sub-barrier fusion is investigated by using a reliable double-folding potential as the bare potential and a new method, recently developed, that allows the disentangling of transfer-channel effects on the fusion cross section.

Nuclear halo structure and conservation of relativistic symmetry are studied within the framework of the relativistic Hartree-Fock-Bogoliubov theory. Giant halos as well as ordinary ones are found in cerium isotopes close to the neutron drip line. Bridged by the $T=0$ channel, the conservation of pseudospin symmetry (PSS) plays an essential role in stabilizing the neutron halo structures. The Fock terms, especially the $\rho$-tensor couplings, not only play a significant role in PSS conservation but also present substantial contributions to the $T=0$ channel, by which the necessity of Fock terms is well demonstrated.

We examine the validity of extending Kramers’ expression for fission width to systems with shape-dependent dissipations. For a system with a shape-dependent dissipation, Kramers’ width obtained with the presaddle dissipation strength is found to be different from the stationary width obtained from the corresponding Langevin equations. It is demonstrated that the probability of a hot compound nucleus undergoing fission depends on both the presaddle and the postsaddle dynamics of collective nuclear motion. The predictions for prescission neutron multiplicity and evaporation residue cross section from statistical model calculations are also found to be different from those obtained from Langevin dynamical calculations when a shape-dependent dissipation is considered. For systems with shape-dependent dissipations, we conclude that the strength of “presaddle dissipation” determined by fitting experimental data in statistical model calculations does not represent the true strength of presaddle dissipation.

The model, introduced in a previous paper, for the description of the octupole and quadrupole degrees of freedom in conditions close to the axial symmetry is used to describe the negative-parity band based on the first octupole vibrational state in nuclei close to the critical point of the U(5)-to-SU(3) phase transition. The situation of ${}^{150}\mathrm{Nd}$ and ${}^{152}\mathrm{Sm}$ is discussed in detail. The positive-parity levels of these nuclei, and also the in-band $E2$ transitions, are reasonably accounted for by the X(5) model. With simple assumptions on the nature of the octupole vibrations, it is also possible to describe the negative-parity sector with comparable accuracy without changing the description of the positive-parity part.

Gamow-Teller (GT) transitions in $\beta$ decays of ${}^9\mathrm{Li}$ and ${}^{11}\mathrm{Li}$ are investigated with theoretical calculations of antisymmetrized molecular dynamics. The calculated $B$(GT) values are small for transitions to low-lying states in Be isotopes, whereas relatively large $B$(GT) values are found for excited states at excitation energy $E_x⩾10$ MeV. The sum of the $B$(GT) values is discussed for each spin-parity of final states. The calculated results seem to be inconsistent with an experimental report of the strongest GT transition from ${}^9\mathrm{Li}$ to the $5/2^{-}$ state of ${}^9\mathrm{Be}$ at $11.8$ MeV.

We first give a brief review of our earlier empirical work on parameter-free difference equations for nuclear spectra and discuss some of the implications. Then we show that a simple quantum mechanical model is capable of explaining and improving our previously suggested recursion relations.

The density dependence of the symmetry energy, instrumental in understanding the behavior of the asymmetric nuclear matter, is investigated within the extended relativistic mean-field (ERMF) model, which includes the contributions from the self- and mixed-interaction terms for the scalar-isoscalar ($\sigma$), vector-isoscalar ($\omega$), and vector-isovector ($\rho$) mesons up to the quartic order. Each of the 26 different parametrizations of the ERMF model employed is compatible with the bulk properties of the finite nuclei. The behavior of the symmetry energy for several parameter sets is found to be consistent with the empirical constraints on them as extracted from the analyses of the isospin diffusion data. The neutron-skin thickness in the ${}^{208}\mathrm{Pb}$ nucleus for these parameter sets of the ERMF model lies in the range of $~0.20-0.24$ fm, which is in harmony with the thickness predicted by the Skyrme Hartree-Fock model. We also investigate the role of various mixed-interaction terms that are crucial for the density dependence of the symmetry energy.

We present dynamic polarization potentials (DPPs), due to both neutron and neutron-pair pickup coupled reaction channels, contributing to the proton-nucleus interaction for the case of ${}^8\mathrm{He}$ at 15.66, 25, and 61.3 MeV/nucleon. The available elastic scattering and transfer data were fitted in coupled reaction channels calculations that allowed full interpartition couplings. In addition, the contributions with various different combinations of coupled reaction channels were considered; we show that this can throw light on the nonlocality of the underlying DPP, for which we determine the local and $L$-independent equivalent.

The $\alpha$-decay half-lives of even-even superheavy elements within the range of proton number $104⩽Z⩽126$, which can be formed by possible cold and hot fusion reactions, are calculated in the framework of various approaches for $\alpha$-decay half-life evaluation and by using the $Q$ values of $\alpha$ transitions obtained within different approximations for atomic masses. The dependencies of $\alpha$-decay half-lives of superheavy elements on model approaches for both the $Q$ values and half-life calculations are discussed in detail.

This article presents results on event-by-event elliptic flow fluctuations in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{\mathit{NN}}}=$ 200 GeV, where the contribution from non-flow correlations has been subtracted. An analysis method is introduced to measure non-flow correlations, relying on the assumption that non-flow correlations are most prominent at short ranges ($\left|\Delta \eta \right|<2$). Assuming that non-flow correlations are of the order that is observed in $p+p$ collisions for long-range correlations ($\left|\Delta \eta \right|>2$), relative elliptic flow fluctuations of approximately 30–40% are observed. These results are consistent with predictions based on spatial fluctuations of the participating nucleons in the initial nuclear overlap region. It is found that the long-range non-flow correlations in $\mathrm{Au}+\mathrm{Au}$ collisions would have to be more than an order of magnitude stronger compared to the $p+p$ data to lead to the observed azimuthal anisotropy fluctuations with no intrinsic elliptic flow fluctuations.

Details of the calculation of two-boson exchange effects in parity-violating elastic $\mathit{ep}$ scattering within a simple hadronic model, including both the nucleon and the $\Delta (1232)$-resonance intermediate states, are presented. We examine the sensitivity of our results with respect to choice of form factors. We emphasize the importance of using correct relations relating $N\to \Delta$ and $\Delta \to N$ transition vertex functions. The $N\Delta$ Coulomb quadrupole transition is found to play an important role at higher $Q^2⩾3.0$ GeV${}^2$. We also elucidate the relation between our results and the well-known result on the $\gamma Z$-boson exchange effect given by Marciano and Sirlin. The effect of the nucleon contribution ${\delta }_N$ to parity asymmetry $A_{\mathrm{PV}}$ is found to be, in general, larger than the corresponding $\Delta$ contribution ${\delta }_{\Delta }$ except at extreme forward angles. Corrections to the extracted values of the strange form factors $G_E^s+\beta G_M^s$ from the HAPPEX, A4, and G0 data are also presented. The total TBE corrections to the extracted values of $G_E^s+\beta G_M^s$ in recent HAPPEX, G0, and A4 experiments are, depending on kinematics, found to be small except in a few cases where they range from $-20.6\%$ to $48.3\%$.

The upper limit of the total cross section for the $\mathit{pn}\to \mathit{pn}{\eta }^{\prime }$ reaction has been determined near the kinematical threshold in the excess energy range from 0 to 24 MeV. The measurement was performed using the COSY-11 detector setup, a deuteron cluster target, and the proton beam of COSY with a momentum of 3.35 GeV$/c$. The energy dependence of the upper limit of the cross section was extracted exploiting the Fermi momenta of nucleons inside the deuteron. Comparison of the determined upper limit of the ratio $R_{{\eta }^{\prime }}=\sigma (\mathit{pn}\to \mathit{pn}{\eta }^{\prime })/\sigma (\mathit{pp}\to \mathit{pp}{\eta }^{\prime })$ with the corresponding ratio for $\eta$-meson production does not favor the dominance of the $N^{*}(1535)$ resonance in the production process of the ${\eta }^{\prime }$ meson and suggests nonidentical production mechanisms for $\eta$ and ${\eta }^{\prime }$ mesons.

There is no reliable evidence for the existence of the $3.076$ MeV ($3^{-}$) level adopted in the ENSDF evaluation for ${}^{56}\mathrm{Fe}$ although it has been reported in a few experiments. Previous reports of the observation of this level appear to be based on an incorrect assignment in early ($e,e^{\prime }$) work. Recent neutron inelastic scattering measurements by Demidov et al. [Phys. At. Nucl. 67, 1884, (2004)] show that the assigned $\gamma$-ray decay of this state does not occur at a level consistent with known properties of inelastic scattering. In the present work the ${}^{56}\mathrm{Fe}$($n,n^{\prime }\gamma$) reaction was used to populate excited states in ${}^{56}\mathrm{Fe}$. Neutrons in the energy range from 1 to 250 MeV were provided by the pulsed neutron source of the Los Alamos Neutron Science Center’s WNR facility. Deexciting $\gamma$ rays were detected with the GEANIE spectrometer, a Compton suppressed array of 26 Ge detectors. The $\gamma$-$\gamma$ data obtained with GEANIE were used to establish coincidence relations between transitions. All previously reported levels up to $E_x=3.6$ MeV excitation energy were observed except for the 3.076 MeV ($3^{-}$) level. The $991$- and $2229$-keV transitions, previously reported to deexcite this level, were not observed in the $\gamma$-$\gamma$ coincidence data obtained in the present experiment. The present work supports the assignment of the $4509.6$ keV level as the first $3^{-}$ excited state in ${}^{56}\mathrm{Fe}$ by observation of two previously known transitions deexciting this state.

For systems with three and four fermions within a single-$j$ shell, analytical expressions for the state energies are presented from a decomposition of the angular momentum. In some important cases the expressions acquire a very simple form. The expression may help us in understanding the structure of isomeric states. The decomposition also makes it possible to construct the algebraic condition for conservation of seniority.

Two methods based on bremsstrahlung were applied to the stable even Mo isotopes for the experimental determination of the photon strength function covering the high excitation energy range above 4 MeV with its increasing level density. Photon scattering was used up to the neutron separation energies $S_n$ and data up to the maximum of the isovector giant resonance (GDR) were obtained by photoactivation. After a proper correction for multistep processes the observed quasicontinuous spectra of scattered photons show a remarkably good match to the photon strengths derived from nuclear photoeffect data obtained previously by neutron detection and corrected in absolute scale by using the new activation results. The combined data form an excellent basis to derive a shape dependence of the $E1$ strength in the even Mo isotopes with increasing deviation from the $N=50$ neutron shell (i.e., with the impact of quadrupole deformation and triaxiality). The wide energy coverage of the data allows for a stringent assessment of the dipole sum rule and a test of a novel parametrization developed previously which is based on it. This parametrization for the electric dipole strength function in nuclei with $A>80$ deviates significantly from prescriptions generally used previously. In astrophysical network calculations it may help to quantify the role the p-process plays in cosmic nucleosynthesis. It also has impact on the accurate analysis of neutron capture data of importance for future nuclear energy systems and waste transmutation.

Nuclear stopping in heavy-ion collisions over a beam energy range from SIS and AGS up to SPS is studied in the framework of the modified Ultrarelativistic Quantum Molecular Dynamics transport model, in which mean field potentials of both formed and “preformed” hadrons (from string fragmentation) and medium-modified nucleon-nucleon elastic cross sections are considered. It is found that nuclear stopping is influenced by both the stiffness of the equation of state and medium modifications of nucleon-nucleon cross sections at SIS energies. At high SPS energies, a two-bump structure is shown in the experimental rapidity distribution of free protons, which can be understood by considering the preformed hadron potentials.

We build up a model to reproduce the experimentally measured $R_{\mathit{AA}}$ of $J/\psi$ near midrapidty in an $\mathrm{Au}+\mathrm{Au}$ collision at $\sqrt{s_{\mathit{NN}}}=200$ GeV. The model takes into account the $J/\psi$ suppression from the quark-gluon plasma and hadron gas as well as the nuclear absorption of primordial charmonia and the regeneration effects at the hadronization stage and hence is a generalization of the two-component model introduced by Grandchamp and Rapp. The improvements in this work are twofold; the addition of the initial local temperature profile and a consistent use of QCD next-to-leading order (NLO) formula for both the dissociation cross section in the hadron gas and the thermal decay widths in the quark-gluon plasma for the charmonium states. The initial local temperature profile is determined from the assumption that the local entropy density is proportional to a formula involving the number densities of the number of participants and of the binary collisions that reproduces the multiplicities of charged particles at chemical freeze-out. The initial local temperature profile brings about a kink in the $R_{\mathit{AA}}$ curve due to the initial melting of $J/\psi$. The initially formed fireball, composed of weakly interacting quarks and gluons with thermal masses that are extracted from lattice QCD, follows an isentropic expansion with cylindrical symmetry. The fit reproduces well the $\mathrm{Au}+\mathrm{Au}$ as well as the $\mathrm{Cu}+\mathrm{Cu}$ data. The same method is applied to predict the $R_{\mathit{AA}}$ expected from the $\mathrm{Pb}+\mathrm{Pb}$ collision at Large Hadron Collider (LHC) energy.

S. H. Liu et al. [Phys. Rev. C 80, 044314 (2009)] have demonstrated that an accurate description of ${}^{137}\mathrm{I}$ may be obtained within the shell model. It seems that they have missed one of the shell model calculations done earlier. They have also missed the earlier theoretical results for ${}^{139}\mathrm{Cs}$, where some of the levels observed in their work were predicted.