The nuclear level densities of ${}^{96,97}\mathrm{Mo}$ are calculated in the framework of superconducting theory. The parameters of nuclear level density are so chosen that the saddle point conditions are satisfied and the best fit to the experimental data yields. Then, using these parameters the energy, the entropy and the spin cut-off factor are calculated as a function of temperature. The curves show structures, reflecting the phase transition from a correlated to an uncorrelated phase. The critical temperature for quenching of pairing correlations is found at $T_c\sim 0.7$–0.9 MeV.

We systematically evaluate the potential energy at the touching configuration for heavy-ion reactions using various potential models. We point out that the energy at the touching point, especially that estimated with the Krappe-Nix-Sierk (KNS) potential, strongly correlates with the threshold incident energy for steep falloff of fusion cross sections observed recently for several systems at extremely low energies. This clearly indicates that the steep fall-off phenomenon can be attributed to the dynamics after the target and projectile touch with each other, e.g., the tunneling process and the nuclear saturation property in the overlap region.

The results of measurements of the production of neutron-rich nuclei by the fragmentation of a ${}^{48}\mathrm{Ca}$ beam at 142 MeV/nucleon are presented. Evidence was found for the production of a new isotope that is the most neutron-rich silicon nuclide, ${}^{44}\mathrm{Si}$, in a net neutron pickup process. A simple systematic framework was found to describe the production cross sections based on thermal evaporation from excited prefragments that allows extrapolation to other weak reaction products.

Experimental data on nuclear dissipation have often been interpreted using one-dimensional model calculations of the Langevin or Fokker-Planck type. In the present work, the influence of the dimensionality of the deformation space on the time dependence of the fission process has been investigated in a systematic and quantitative way. In particular, the dependence of the transient time and the stationary value of the fission rate on the number of collective coordinates involved in Langevin calculations is investigated for the one-body and two-body dissipation mechanisms. We show that the results of Langevin-type calculations change appreciably if the deformation space is extended up to three dimensions.

The Nambu–Jona-Lasinio model with a Polyakov loop is extended to the finite isospin chemical potential case, which is characterized by the simultaneous coupling of the pion condensate, chiral condensate, and Polyakov loop. The pion condensate, chiral condensate, and Polyakov loop as functions of temperature and isospin chemical potential are investigated by minimizing the thermodynamic potential of the system. The resulting $(T,{\mu }_I)$ phase diagram is studied with emphasis on the critical point and Polyakov loop dynamics. The tricritical point for the pion superfluidity phase transition is confirmed, and the phase transition for isospin symmetry restoration in the high isospin chemical potential region perfectly coincides with the crossover phase transition for the Polyakov loop. These results agree with the lattice QCD data.

We calculate the axial $N\to \Delta (1232)$ and $N\to N^{*}(1440)$ transition form factors in a chiral constituent quark model. As required by the partial conservation of axial current (PCAC) condition, we include one- and two-body axial exchange currents. We compare the axial $N\to \Delta (1232)$ form factors with previous quark model calculations that use only one-body axial currents, and with experimental analyses. The paper provides the first calculation of all weak axial $N\to N^{*}(1440)$ form factors. Our main result is that exchange currents are very important for certain axial transition form factors. In addition to improving our understanding of nucleon structure, the present results are relevant to the neutrino-nucleus scattering cross section predictions needed in the analysis of neutrino mixing experiments.

The phase transition in odd nuclei when the underlying even-even core nuclei experience a transition from spherical to deformed γ-unstable shapes is investigated. The odd particle is assumed to be moving in the three single-particle orbitals $j=1/2,3/2$, and 5/2 . At the critical point in the phase transition, an analytic solution to the corresponding Bohr Hamiltonian, called E(5/12), is worked out. Energy spectra and electromagnetic transitions and moments are presented. The same problem is also attacked in the framework of the interacting boson-fermion model (IBFM). Two different Hamiltonians are used. The first one is constructed ad hoc so as to mimic the situation in the E(5/12) model. The second one leads to the occurrence of the ${\mathrm{O}}^B(6)\otimes {\mathrm{U}}^F(12)$ symmetry when the boson part approaches the O(6) condition. The entire transition line is studied with this Hamiltonian and, in particular, the critical point. Both IBFM calculations at the critical point are consistent with the E(5/12) results.

In this work, the bulk and thermodynamic properties of nonrelativistic hot nuclear matter—the mean internal energy per unit volume, the saturation density and the corresponding internal energy per nucleon, the pressure, the entropy per unit volume, the heat capacity per unit volume, and the chemical potential—are studied within the static fluctuation approximation (SFA). The basic input is the well-known Reid68 and Reid93 soft-core potentials, with special emphasis on three channels that have different spin and isospin—namely, the ${}^1{S}_0$-channel as well as the ${}^3{S}_1\text{−}{}^3{D}_1$ and ${}^3{P}_2\text{−}{}^3{F}_2$ coupled channels. Finally, a full-fledged calculation is presented using the Reid93 potential for all channels $J⩽2$. Wherever possible, comparisons are made with previous calculations. It is concluded that SFA is valid for hot nuclear matter over a wide range of temperatures ($⩽50$ MeV).

We investigate classical and quantum signatures of increased regularity in the Alhassid-Whelan semiregular arc inside the symmetry triangle of the interacting boson model. A significant bunching/antibunching pattern of quantum levels, similar to that observed along the O(6)-U(5) transition, is found in the $0^{+}$ energy spectrum and related to a crossover of two specific families of classical regular orbits slightly above $E=0$. We also discuss the degeneracy of β and γ bandheads in a region close to the arc and the relation to regularity in the geometric model.

We construct a phenomenological three-nucleon force (3NF) model that gives a good description of polarization observables in elastic nucleon-deuteron ($N\text{−}d$) scattering at a low energy together with a realistic nucleon-nucleon force and a 3NF arising from the exchange of two pions. Parameters of the model, which consists of spin-independent, spin-orbit, and tensor components, are determined to reproduce the three-nucleon binding energy and polarization observables in $N\text{−}d$ scattering at 3 MeV. Predictions of the 3NF model on $N\text{−}d$ polarization observables at higher energies are examined, and the effects of each component on the observables are investigated.

With the Doppler Shift Attenuation Method, quadrupole transition moments $Q_t$ were determined for the two recently proposed triaxial strongly deformed (TSD) bands in ${}^{163}\mathrm{Tm}$. The measured $Q_t$ values indicate that the deformation of these bands is larger than that of the yrast signature partners. However, the measured values are smaller than those predicted by theory. This observation appears to be valid for TSD bands in several nuclei of the region.

Short range correlations are introduced using a Jastrow factor in a relativistic approach to the equation of state of the infinite nuclear matter in the framework of the Hartree-Fock approximation. The pion exchange, including the tensor contribution, is taken into account. It is shown that both the tensor contribution of pion exchange and short range correlations soften the equation of state. Neutron matter with correlations presents no minimum at low densities.

The momentum dependent $K^{-}$-nucleus optical potentials are obtained based on the relativistic mean-field theory. By considering the quarks coordinates of $K^{-}$ meson, we introduced a momentum-dependent “form factor” to modify the coupling vertexes. The parameters in the form factors are determined by fitting the experimental $K^{-}$-nucleus scattering data. It is found that the real part of the optical potentials decrease with increasing $K^{-}$ momenta, however the imaginary potentials increase at first with increasing momenta up to $P_k=450\sim 550$ MeV and then decrease. By comparing the calculated $K^{-}$ mean free paths with those from $K^{-}n/K^{-}p$ scattering data, we suggested that the real potential depth is $V_0\sim 80$ MeV, and the imaginary potential parameter is $W_0\sim 65$ MeV.

In this Brief Report we estimate the influence of nonlinear gluon evolution in the production of prompt photons at the Large Hadron Collider (LHC) $\mathit{pp}$ collider. We assume the validity of collinear factorization and consider the EHKQS parton distributions, which are solutions of the GLR-MQ evolution equations and describe quite well the DESY $\mathit{ep}$ HERA data, as input in our calculations. We find that both single and double photon production are enhanced for low-$p_T$ photons and central rapidities, while this effect is absent for the high-$p_T$ photons. The implications of this effect for the quark-gluon plasma searches and for the quantum chromodynamics (QCD) background to Higgs are also discussed.

We present a new Hartree-Fock-Bogoliubov mass model, HFB-14, that is fitted to the fission data through adjustment of a vibrational term in the phenomenological collective correction. The rms deviation of the model from the 2149 measured masses of nuclei with $Z,N⩾8$ is 0.729 MeV. The rms deviation for all 77 primary barriers listed in the RIPL-2 data compilation is 1.31 MeV, and only 0.67 MeV for the 52 primary barriers of nuclei lower than 9 MeV, the ones of greater astrophysical interest. A similar accuracy is obtained (0.65 MeV) for the 45 secondary experimental barriers necessary for a reliable calculation of fission probabilities.

The generation of sizable angular momenta in fragments formed in low-energy nuclear fission is described microscopically within the general quantum-mechanical framework of orientation pumping due to the Heisenberg uncertainty principle. Within this framework, we make use of the results of Skyrme-Hartree-Fock plus BCS-pairing calculations of fragment deformabilities to deduce a distribution of fission-fragment spins as a function of the fragment total excitation energy. We consider a fragmentation corresponding to a pair of deformed fragments and for which fission data are available. The properties of the scission configurations determine to a large extent the fission-fragment spins. This is why we pay particular attention to quantitatively defining the scission configurations and to studying the various implications of such a specific choice. A fair qualitative agreement with data is demonstrated and discussed within the limits of the simple scission-configuration model used here.

The fusion-evaporation reaction involving a 175 MeV ${}^{36}\mathrm{S}$ beam and a ${}^{124}\mathrm{Sn}$ target was performed, and the emitted γ rays were observed with the Gammasphere spectrometer. Significant additions to the level scheme of ${}^{152}\mathrm{Gd}$ were made in spite of the relative weakness of the α4n exit channel, being only ∼2% of the total fusion cross-section. The high-spin behavior of ${}^{152}\mathrm{Gd}$ was compared with that of other $N=88$ nuclei. A striking similarity was observed with ${}^{154}\mathrm{Dy}$ and it is therefore suggested that the angular-momentum-induced shape changes that take place in ${}^{154}\mathrm{Dy}$ also occur in ${}^{152}\mathrm{Gd}$ in the 30–40ħ spin range. This is supported by Cranked Nilsson-Strutinsky calculations which were used to interpret the high-spin bands. It is found that a better agreement between calculation and experiment is obtained if the $Z=64$ shell gap increases with a decreasing number of valence particles outside the doubly-closed ${}_{64}^{146}{\mathrm{Gd}}_{82}$ nucleus.

We study the temperature dependence of discretization errors in nuclear lattice simulations. We find that for systems with strong attractive interactions the predominant error arises from the breaking of Galilean invariance. We propose a local “well-tempered” lattice action which eliminates much of this error. The well-tempered action can be readily implemented in lattice simulations for nuclear systems as well as cold atomic Fermi systems.

${}^{83}\mathrm{Nb}$ has been studied in order to locate the upper extent of large deformation in the $N\sim Z\sim 40$ region and ascertain its sign and magnitude. The decay scheme has been considerably extended by studying gamma decay following the ${}^{58}\mathrm{Ni}$(${}^{28}\mathrm{Si}$, $p2n$)${}^{83}\mathrm{Nb}$ reaction at 204 and 215 MeV and using Gammasphere. Both signature partners of two rotational bands have been observed. The band properties support a $I^{\pi }={\frac{5}{2}}^{+}$ ground state spin assignment. The in-band branching ratios and multipole mixing ratios were found to be consistent with significant prolate deformation, as found in other $N=42$ isotones. The bands are particularly similar to the isotone ${}^{81}\mathrm{Y}$. A projected shell model analysis has been performed which provides good reproduction of the features of both bands. The calculations indicate the nucleus to be nearly axially symmetric. ${}^{82,83}\mathrm{Nb}$ may be the heaviest nuclei in the $A\sim 80$ region with large deformation. The deformation is predicted to fall in heavier systems approaching ${}^{100}\mathrm{Sn}$. The conditions appear to be right for the occurrence of $K$ isomers.