A model for the dissociation of the $J/\psi$ is proposed, where chiral symmetry is properly implemented. Abnormal parity interactions and mesonic form factors naturally arise from the underlying quark substructure. Analytic confinement of the light quarks is obtained through an appropriate choice of quark interaction kernels. Dissociation cross sections of the $J/\psi$ by either a π or a ρ meson are then evaluated and discussed.

We present an equation of state and the composition of low-density supernova matter composed of light nuclei with mass number $A⩽13$. We work within the quasiparticle gas model, which accounts for bound states with decay time scales larger than the relevant time scale of supernova and protoneutron star evolution. The mean-field contribution is included in terms of Skyrme density functional. Deuterons, tritons, and ${}^3\mathrm{H}$(e) nuclei appear in matter in concentrations that are substantially higher than those of heavier nuclei. We calculate the critical temperature of deuteron condensation in such matter and demonstrate that the appearance of clusters substantially lowers the critical temperature.

A new interpretation of two-nucleon pair transfer in collective nuclei is presented. It differs from traditional models and unifies, within a consistent framework, the entire range of monopole pair-transfer phenomenology in collective nuclei. This includes the well-known examples of large cross sections to excited $0^{+}$ states in phase transitional nuclei, and small ones in many other nuclei, but also predicts large cross sections elsewhere under particular circumstances. These predictions can be tested experimentally.

We discuss how the different estimates of elliptic flow are influenced by flow fluctuations and nonflow effects. It is explained why the event-plane method yields estimates between the two-particle correlation methods and the multiparticle correlation methods. It is argued that nonflow effects and fluctuations cannot be disentangled without other assumptions. However, we provide equations where, with reasonable assumptions about fluctuations and nonflow, all measured values of elliptic flow converge to a unique mean $v_{2,\mathrm{PP}}$ elliptic flow in the participant plane and, with a Gaussian assumption on eccentricity fluctuations, can be converted to the mean $v_{2,\mathrm{RP}}$ in the reaction plane. Thus, the 20% spread in observed elliptic flow measurements from different analysis methods is no longer mysterious.

This article presents an investigation into the pycnonuclear reaction rates in dense crustal matter of neutron stars contaminated with strange quark matter nuggets. The presence of such nuggets in the crustal matter of neutron stars would be a natural consequence if Witten's strange quark matter hypothesis is correct. The methodology presented in this article is a recreation of a recent representation of nuclear force interactions embedded within pycnonuclear reaction processes. The study then extends the methodology to incorporate distinctive theoretical characteristics of strange quark matter nuggets, like their low charge-per-baryon ratio, and then assesses their effects on the pycnonuclear reaction rates. Particular emphasis is put on the impact of color superconductivity on the reaction rates. Depending on whether quark nuggets are in this novel state of matter, their electric charge properties vary drastically, which turns out to have a dramatic effect on the pycnonuclear reaction rates. Future nuclear fusion network calculations may thus have the potential to shed light on the existence of strange quark matter nuggets and on whether they are in a color superconducting state, as suggested by QCD.

The electric dipole excitation of various nuclei is calculated with a Random Phase Approximation phenomenological approach. The evolution of the strength distribution in various groups of isotopes of oxygen, calcium, zirconium, and tin is studied. The neutron excess produces $E1$ strength in the low-energy region. Indexes to measure the collectivity of the excitation are defined. We studied the behavior of proton and neutron transition densities to determine the isoscalar or isovector nature of the excitation. We observed that in medium-heavy nuclei the low-energy $E1$ excitation has characteristics rather different than those exhibited by the giant dipole resonance. This new type of excitation can be identified as a pygmy dipole resonance.

Our understanding of nuclear fission, a fundamental nuclear decay, is still incomplete due to the complexity of the process. In this paper, we describe a study of spontaneous fission using the symmetry-unrestricted nuclear density functional theory. Our results show that the observed bimodal fission can be explained in terms of pathways in multidimensional collective space corresponding to different geometries of fission products. We also predict a new phenomenon of trimodal spontaneous fission for some rutherfordium, seaborgium, and hassium isotopes.

Inclusive nucleon spectra from deuteron breakup reactions on ${}^7\mathrm{Li}$ are analyzed in terms of the continuum discretized coupled channels theory for the elastic breakup process and the Glauber model for the nucleon stripping process. Both theoretical models use the same phenomenological nucleon optical potential of ${}^7\mathrm{Li}$ and have no other free parameters. The calculations reproduce well a prominent bump observed around half the incident energy in experimental inclusive spectra of 40-MeV ($d,\mathit{xn}$) and 100-MeV ($d,\mathit{xp}$) reactions at forward angles. The analysis shows that the stripping process is more important than the elastic breakup process in deuteron breakup reactions on ${}^7\mathrm{Li}$.

We have analyzed ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ inelastic scattering to the single $2_1^{+}$ and $3_1^{-}$ channels at incident energies of $E_{\mathrm{lab}}=350$ and 1120 MeV by a microscopic coupled-channel calculation. We have found that the strong rotational coupling among the channels of the $\alpha +$${}^{12}\mathrm{C}$${}_{\mathrm{g}.\mathrm{s}.}$ type cluster states plays an important role in reproducing the angular distribution of the $2_1^{+}$ channel for both energies. We have also found that the coupling with the $0_2^{+}$, $2_1^{+}$, and $4_1^{+}$ channels as well as those among the shell channels has a large effect on the $3_1^{-}$ channel cross sections at $E_{\mathrm{lab}}=350$ MeV. However, their absolute values could not be reproduced by our calculation, unless we assumed that the strengths of the $3_1^{-}\to 0_2^{+},2_1^{+},4_1^{+}$ transitions were unphysically strong.

We calculate the important quantity of superfluid hydrodynamics, the relativistic entrainment matrix for a nucleon-hyperon mixture at arbitrary temperature. In the nonrelativistic limit this matrix is also termed the Andreev-Bashkin or mass-density matrix. Our results can be useful for modeling the pulsations of massive neutron stars with superfluid nucleon-hyperon cores and for studies of the kinetic properties of superfluid baryon matter.

The temperature dependence of the nuclear matter isovector symmetry energy coefficient (${\mathcal{A}}_{0,1}$) is investigated in the framework of the generalized nuclear polarizability with Skyrme interactions, as worked out in previous articles [F. L. Braghin, Nucl. Phys. A665, 13 (2000); Phys Rev. C 71, 064303 (2005); Int J. Mod. Phys. E 12, 755 (2003)]. The variation of ${\mathcal{A}}_{0,1}(T)$ is very small (of the order of 1 MeV) for temperatures ($T$) in the range of 0 and 18 MeV. Different behaviors with temperature are found to strongly depend on the Skyrme parametrization, in particular at densities lower than the saturation density ${\rho }_0$.

Break-up fragmentation patterns together with kinetic and configurational energy fluctuations are investigated in the framework of a microcanonical model with fragment degrees of freedom over a broad excitation energy range. As long as fragment partitioning is approximately preserved, energy fluctuations are found to be rather insensitive to both the way in which the freeze-out volume is constrained and the trajectory followed by the system in the excitation-energy–freeze-out volume space. Due to hard-core repulsion, the freeze-out volume is found to be populated nonuniformly, its highly depleted core giving the source a bubble-like structure. The most probable localization of the largest fragments in the freeze-out volume may be inferred experimentally from their kinematic properties, largely dictated by Coulomb repulsion.

Precision measurements of ${}^{238}\mathrm{U}$$(n,n^{\text{'}}\gamma )$ and ${}^{238}\mathrm{U}$$(n,2n\gamma )$ partial cross sections have been performed at Triangle Universities Nuclear Laboratory (TUNL) to improve crucial data needed for testing nuclear reaction models in the actinide mass region. A pulsed and monoenergetic neutron beam was used in combination with high-resolution γ-ray spectroscopy to obtain partial cross sections for incident neutron energies between 5 and 14 MeV. γ-ray yields were measured with high-purity germanium clover and planar detectors. Measured partial cross-section data are compared with previous results using white and monoenergetic neutron beams and calculations from the GNASH and TALYS Hauser-Feshbach statistical-model codes. Present experimental results are in fair to good agreement with most of the existing data for the ${}^{238}\mathrm{U}$$(n,n^{\text{'}}\gamma )$ reaction. However, significant discrepancies are observed for the ${}^{238}\mathrm{U}$$(n,2n\gamma )$ reaction.

The response of the QCD vacuum to very large static external magnetic fields ($qB\gg {\Lambda }_{\mathrm{QCD}}^2$) is studied. In this regime, the magnetization of the QCD vacuum is naturally described via perturbative QCD. Combining pQCD and the Schwinger proper time formalism, we calculate the magnetization of the QCD vacuum due to a strong magnetic field at leading order (one-loop) to be proportional to $B\log B$. We show that the leading perturbative correction (two-loop) vanishes.

The oblate-prolate shape coexisting/mixing phenomena in proton-rich ${}^{68,70,72}\mathrm{Se}$ are investigated by means of the adiabatic self-consistent collective coordinate (ASCC) method. The one-dimensional collective path and the collective Hamiltonian describing the large-amplitude shape vibration are derived in a fully microscopic way. The excitation spectra, $B(E2)$ and spectroscopic quadrupole moments are calculated by requantizing the collective Hamiltonian and solving the collective Schrödinger equation. The basic properties of the coexisting two rotational bands in low-lying states of these nuclei are well reproduced. It is found that the oblate-prolate shape mixing becomes weak as the rotational angular momentum increases. We point out that the rotational energy plays a crucial role in causing the localization of the collective wave function in the $(\beta ,\gamma )$ deformation space.

The energy spectra of the parent and daughter nuclei in the β decays (${}^{121\text{−}127}\mathrm{Xe}$,${\beta }^{+}$${}^{121\text{−}127}\mathrm{I}$) are considered in the interacting boson fermion model (IBFM-2) with the $g_{7/2},d_{5/2},d_{3/2},s_{1/2}$, and $h_{11/2}$ single-particle orbitals. Electromagnetic transition probabilities and branching ratios in odd ${}^{121\text{−}127}\mathrm{I}$ isotopes are investigated. Special attention is given to the occurrence of mixed symmetry states, and the $F$-spin structures of the wave functions are analyzed. The $\log {}_{10}\mathit{ft}$ values of the allowed β decay transitions are calculated. It is found that the IBFM-2 results agree with the experimental data quite well.

An experiment was carried out to explore heavy ion incomplete fusion reaction dynamics, within the framework of the break-up fusion model, at energies near and above the Coulomb barrier. Excitation functions for several radionuclides produced via $\mathit{xn}$, $\mathit{pxn}$, and $\alpha \mathit{xn}$ channels were measured in the ${}^{16}\mathrm{O}+{}^{181}\mathrm{Ta}$ system at energies of $\approx 76\text{−}100$ MeV. The experimental excitation functions were compared with those calculated using the theoretical model code PACE4. It was observed that excitation functions of $\mathit{xn}/\mathit{pxn}$ channels are in good agreement with theoretical predictions. However, a significant enhancement in the measured excitation functions of $\alpha$-emitting channels was observed and attributed to the incomplete fusion processes. The incomplete fusion fraction ($F_{\mathrm{ICF}}$) that gives the relative importance of complete and incomplete fusion processes was found to increase with energy. The results are discussed in terms of $\alpha$-cluster structure of the projectile on various fusion reactions.