We study the relevance of the energy correlation produced by the two-body spin-orbit coupling present in realistic nucleon-nucleon interaction potentials. To this purpose, the neutron matter equation of state (EoS) is calculated with the realistic two-body Argonne $v_8^{\prime }$ potential. The shift occurring in the EoS when spin-orbit terms are removed is taken as an estimate of the spin-orbit correlation energy. Results obtained within the Bethe-Brueckner-Goldstone expansion, extended up to three hole-line diagrams, are compared with other many-body calculations recently presented in the literature. In particular, excellent agreement is found with the Green’s function Monte Carlo method. This agreement indicates the present theoretical accuracy in the calculation of the neutron matter EoS.

Isotopic yields for light particles and intermediate mass fragments have been measured for central ${}^{112}\mathrm{Sn}+{}^{112}\mathrm{Sn}$, ${}^{112}\mathrm{Sn}+{}^{124}\mathrm{Sn}$, ${}^{124}\mathrm{Sn}+{}^{112}\mathrm{Sn}$, and ${}^{124}\mathrm{Sn}+{}^{124}\mathrm{Sn}$ collisions at $E∕A=50\text{MeV}$ and compared with predictions of stochastic mean field calculations. These calculations predict a sensitivity of the isotopic distributions to the density dependence of the asymmetry term of the nuclear equation of state. However, the secondary decay of the excited fragments modifies significantly the primary isotopic distributions and these modifications are rather sensitive to theoretical uncertainties in the excitation energies of the hot fragments. The predicted final isotope distributions are narrower than the experimental data and the sensitivity of the predicted yields to the density dependence of the asymmetry term is reduced.

Two soft-photon amplitudes, the Low amplitude and the two-$u$–two-$t$ special amplitude, agree with one another in the case of $np\gamma$ but disagree significantly in the case of $pp\gamma$. The two-$u$–two-$t$ special amplitude describes well the available $pp\gamma$ cross section data. The relationship between the two amplitudes as well as the reason they agree and disagree is explored. Using these two soft-photon amplitudes plus a one-boson exchange amplitude, the contribution of the proton and neutron anomalous magnetic moments to $pp\gamma$ and $np\gamma$ has been investigated for projectile energies above $150\text{MeV}$ and for laboratory scattering angles lying between $8°$ and $35°$. The anomalous magnetic moment contribution was found to be significant in the $pp\gamma$ process but insignificant in the $np\gamma$ process. Additional aspects of the bremsstrahlung mechanism are discussed. Our findings play an important role in understanding the similarities and differences between the Low amplitude and the two-$u$–two-$t$ special amplitude as well as why the two-$u$–two-$t$ special amplitude calculation agrees well with the available $pp\gamma$ cross section data.

We evaluate the in-medium $D$- and $\overline{D}$-meson masses in hot hadronic matter induced by interactions with the light hadron sector described in a chiral SU(3) model. The effective Lagrangian approach is generalized to SU(4) to include charmed mesons. We find that the $D$ mass drops substantially at finite temperatures and densities, which open the channels of the decay of the charmonium states $\left({\Psi }^{\prime },{\chi }_c,J∕\Psi \right)$, to $D\overline{D}$ pairs in the thermal medium. The effects of vacuum polarizations from the baryon sector on the medium modification of the $D$-meson mass relative to those obtained in the mean field approximation are investigated. The results of the present work are compared to calculations based on the QCD sum rule approach, the quark-meson coupling model, chiral perturbation theory, as well as to studies of quarkonium dissociation using heavy quark potential from lattice QCD.

Rotational bands in ${}^{175}\mathrm{Lu}$ have been extended through investigation with the $(n,n^{\prime }\gamma )$ reaction. Spallation neutrons bombarded Lu samples, and the resulting $\gamma$ rays were detected in a large-scale Compton-suppressed Ge detector array. Prompt- and delayed-$\gamma \gamma$ coincidences have been used to extend the $5∕2^{+}\left[402\right]$ band to spin $17∕2$, the $3∕2^{+}\left[411\right]$ band to spin $11∕2$, the $1∕2^{+}\left[411\right]$ band to spin $15∕2$, and the $1∕2^{-}\left[541\right]$ and $9∕2^{-}\left[514\right]$ bands to spin $21∕2$. A new band, based on the $7∕2^{-}\left[523\right]$ configuration, is tentatively assigned from its bandhead to spin $13∕2$. The three-quasiparticle $K^{\pi }=19∕2^{+}$ isomer is confirmed and its half-life determined to be $984\pm 13(\text{stat}.)\pm 30(\text{sys}.)$ $\mu \mathrm{s}$, in agreement with previous results.

Experimental studies have obtained the caloric curve of nuclear matter from heavy ion collisions and studied its size dependence. This work investigates the thermodynamics of a heavy ion collision and concludes that the plateau temperature of the caloric curve is determined by the entropy generated during the initial part of the collision, which in turn is related to the size of the system.

The liquid-gas phase transition in infinite asymmetric nuclear matter is studied with the ${\text{SkM}}^{*}$ interaction. In its light, the said transition is investigated in finite nuclei in a heated liquid-drop model where the drop is assumed to be in thermodynamic equilibrium with the vapor emanated from it. Results for caloric curve, isospin fractionation, heat capacity, and entropy are presented. The results of the calculations in this model are suggestive of a continuous phase transition.

We study the four-body decays $J∕\psi \to N\overline{N}\mathit{meson}\mathit{meson}$ using a chiral unitary approach to account for the meson meson final state interaction (FSI). The calculation of the $J∕\psi \to N\overline{N}{\pi }^{+}{\pi }^{-}$ process properly reproduces the experimental data after taking the FSI of mesons and the contribution of intermediate $\rho$ meson into account. The isoscalar resonances $\sigma ,f_0\left(980\right)$ and the isovector resonance $a_0\left(980\right)$ are generated through the FSI of the mesons in the channels $J∕\psi \to N\overline{N}{\pi }^0{\pi }^0$ and $J∕\psi \to N\overline{N}{\pi }^0\eta$, respectively. We also calculate the two mesons invariant mass distribution and the partial decay width of $J∕\psi \to N\overline{N}{K}^{+}{K}^{-}$ and $J∕\psi \to N\overline{N}{K}^0{\overline{K}}^0$, on which there is still no experimental data available.

The relativistic Hartree-Bogoliubov (RHB) model is employed in the mapping of the proton drip line in the suburanium region and for superheavy elements. The RHB prediction for the last bound isotope of each odd-$Z$ element in these mass regions, and the ground-state quadrupole deformations of nuclei at the drip line, is compared with several mass formulas and with recent experimental data on the location of the proton drip line in the suburanium region.

We calculate the nucleonic equation of state within the Brueckner-Bethe-Goldstone formalism using the Argonne ${\upsilon }_{18}$ two-body interaction and a three-body interaction. We adopt two different three-body forces: the phenomenological Urbana IX model and a microscopic meson-exchange force including nucleon virtual excitations and nucleon-antinucleon excitations. We compare their respective predictions regarding the structure of neutron stars, in particular the mass-radius relation.

In view of the striking implications of the recently measured $g$ factors for the $2_1^{+}$ states of ${}^{42}\mathrm{Ca}$ and ${}^{44}\mathrm{Ca}$ we have supplemented this study with similar measurements on ${}^{46}\mathrm{Ca}$. For all three isotopes we utilized the powerful technique of projectile Coulomb excitation in inverse kinematics combined with transient magnetic fields. In contrast to the positive $g\left(2_1^{+}\right)$ factor values for both ${}^{42,44}\mathrm{Ca}$, implying large admixtures of particle-hole configurations from ${}^{40}\mathrm{Ca}$ core excitations, the $g$ factor of ${}^{46}\mathrm{Ca}\left(2_1^{+}\right),g=-0.19\left(12\right)$, is negative. This result is in very definite disagreement with the large positive value predicted by the large scale shell model (LSSM) calculations which included $sd$ shell core excitations into the $fp$ shell and accounted well for corresponding ${}^{42,44}\mathrm{Ca}$ results. The $B\left(E2;0_1^{+}\to 2_1^{+}\right)$ deduced from the remeasured ${}^{46}\mathrm{Ca}\left(2_1^{+}\right)$ lifetime is indeed substantially smaller than the corresponding value for ${}^{42}\mathrm{Ca}$, again contrary to LSSM predictions. Both $g\left(2_1^{+}\right)$ and $B\left(E2\right)$ in ${}^{46}\mathrm{Ca}$ can be explained by full $fp$ shell model calculations using the FPD6 interaction without invoking core excitations.

In the recent experiments designed to synthesize the element 115 in the ${}^{243}\mathrm{Am+}{}^{48}\mathrm{Ca}$ reaction at Dubna in Russia, three similar decay chains consisting of five consecutive $\alpha$ decays and another different decay chain of four consecutive $\alpha$ decays are detected, and the decay properties of these synthesized nuclei are claimed to be consistent with consecutive $\alpha$ decays originating from the parent isotopes of the new element 115, ${}^{288}115$ and ${}^{287}115$, respectively. Here in the present work, the recently developed deformed relativistic mean field$+$BCS method with a density-independent $\delta$ function interaction in the pairing channel is applied to the analysis of these newly synthesized superheavy nuclei. The calculated $\alpha$-decay energies and half-lives agree well with the experimental values and with those of the macroscopic-microscopic finite-range droplet model with folded-Yukawa single-particle potentials and Yukawa-plus-exponential model with Woods-Saxon single-particle potentials. In the mean field Lagrangian, the TMA parameter set is used. Particular emphasis is laid on the influence to both the ground-state properties and energy surfaces introduced by different treatments of pairing. Two different effective interactions in the particle-particle channel, i.e., the constant pairing and the density-independent $\delta$-function interaction, together with the blocking effect are discussed in detail.

The polarization of quarkonium states produced in hadron collisions exhibits strong nonperturbative effects—for example, at small transverse momentum $p_t$ charmonia appear unpolarized, in sharp contradiction to the predictions of perturbation theory. The quark-gluon plasma is expected to screen away the nonperturbative physics; therefore those quarkonia which escape from the plasma should possess polarization as predicted by perturbative QCD. We estimate the expected $J∕\psi$ polarization at small $p_t$, and find that it translates into the asymmetry of the $e^{+}{e}^{-}\left({\mu }^{+}{\mu }^{-}\right)$ angular distribution $W\left(\theta \right)\sim 1+\alpha {\cos }^2\theta$, with $\alpha \simeq 0.35–0.4$.

The $\left(K_{\text{stopped}}^{-},{\pi }^0\right)$ strangeness and charge changing reaction was investigated by producing a ${}_{\Lambda }{}^{12}\mathrm{B}$ hypernucleus from a carbon target. The branching ratio for $K^{-}$ capture to the ground and $p$-shell states of this hypernucleus was found to be $(0.28\pm 0.08)\times {10}^{-3}$ and $(0.35\pm 0.09)\times {10}^{-3}$, respectively, which after correction for isospin was lower than a previously measured value for the ${}^{12}\mathrm{C}(K_{\text{stopped}}^{-},{\pi }^{-}){}_{\Lambda }{}^{12}\mathrm{C}$ reaction, but still above the theoretical predictions for the ground state. The experiment obtained a missing-mass resolution comparable to in-flight reactions, however the higher background and lower selectivity of the $K_{\text{stopped}}^{-}$ reaction limits its usefulness in the study of new hypernuclear species.

Superdeformed bands in ${}^{88}\mathrm{Mo}$, ${}^{89}\mathrm{Tc}$, and ${}^{91}\mathrm{Tc}$ were populated using a ${}^{40}\mathrm{Ca}$ beam with an energy of $185\text{MeV}$, impinging on a backed ${}^{58}\mathrm{Ni}$ target. $\gamma$ rays and charged particles emitted in the reactions were detected using the Gammasphere Ge detector array and the CsI(Tl) array Microball. Average transition quadrupole moments $Q_t$, with significantly improved accuracy compared to earlier work, were deduced for the bands using the residual doppler shift technique. The experimental results were included into a systematic study of the $Q_t$ values throughout the superdeformed mass 80–90 region. The superdeformed shell gaps are predicted to move towards larger deformations with increasing $Z$ and $N$ in this mass region. This trend is confirmed by the experimental $Q_t$ values.

The recently proposed fully renormalized quasiparticle random-phase approximation (QRPA), which fulfills the Ikeda sum rule exactly, is applied to the two-neutrino double $\beta$ decay of ${}^{76}\mathrm{Ge}$, ${}^{82}\mathrm{Se}$, ${}^{100}\mathrm{Mo}$, ${}^{116}\mathrm{Cd}$, ${}^{128}\mathrm{Te}$, and ${}^{130}\mathrm{Xe}$. The results obtained are compared with those of other approaches, standard QRPA and self-consistent QRPA. The similarities and the differences among the methods are discussed. The influence of the restoration of the Ikeda sum rule on the $2\nu \beta \beta$-decay amplitude is analyzed.

The Gamow-Teller (GT) states are investigated in relativistic models. The Landau-Migdal (LM) parameter is introduced in the Lagrangian as a contact term with the pseudovector coupling. In the relativistic model the total GT strength in the nucleon space is quenched by about $12\%$ in nuclear matter and by about $6\%$ in finite nuclei, compared with the Ikeda-Fujii-Fujita sum rule. The quenched amount is taken by nucleon-antinucleon excitations in the timelike region. Because of the quenching, the relativistic model requires a larger value of the LM parameter than nonrelativistic models in describing the GT excitation energy. On the other hand, the effect of the Pauli blocking terms is not important for the GT states.

We develop a model of off-mass-shell pairing correlations in nuclear systems, which is based on the meson-exchange picture of nuclear interactions. The temporal retardations in the model are generated by the Fock-exchange diagrams. The kernel of the complex gap equation for baryons is related to the in-medium spectral function of mesons, which is evaluated nonperturbatively in the random phase approximation. The model is applied to the low-density neutron matter in neutron star crusts by separating the interaction into a long-range one-pion-exchange component and a short-range component parametrized in terms of Landau Fermi liquid parameters. The resulting Eliashberg-type coupled nonlinear integral equations are solved by an iterative procedure. We find that the self-energies extend to off-shell energies of the order of several tens of MeV. At low energies the damping of the neutron pair correlations due to the coupling to the pionic modes is small, but becomes increasingly important as the energy is increased. We discuss an improved quasiclassical approximation under which the numerical solutions are obtained.

Statistical model calculations have been performed using the rotating finite range and the Thomas-Fermi models for fission barriers. The results have been compared with the existing cross sections for ${}^{40}\mathrm{Ar}+{}^{148}\mathrm{Sm}$ and ${}^{86}\mathrm{Kr}+{}^{104}\mathrm{Ru}$ systems. Analyses show that the use of Thomas-Fermi fission barrier without any shell correction gives the best fit to the experimental cross sections. This observation is in contrast to the conclusion drawn from $\gamma$-ray fold measurements for ${}^{48}\mathrm{Ca}+{}^{142}\mathrm{Nd}$ and ${}^{80}\mathrm{Se}+{}^{110}\mathrm{Pd}$ systems reported earlier.