International Journal of Modern Physics E

Review of calculation results for astrophysical $S$-factor of the ${}^{14}$N${(p,\gamma )}^{15}$O capture reaction in the $p^{14}$N channel of ${}^{15}$O was presented. It was carried out in the frame of the modified potential cluster model (MPCM) taking into account resonances in the ${}^{15}$O spectrum up to 3.2MeV at energy of incident protons varying of 30keV to 5MeV. It is possible to describe experimental data for the astrophysical $S$-factors of the radiative proton capture on ${}^{14}$N to five excited states of ${}^{15}$O at excitation energies of 5.18MeV to 6.86MeV, only under assumption, that all five resonances are $D$ scattering waves. Quality new physical interpretation of the capture mechanism is discussed in this channel to the ground state of ${}^{15}$O. We assumed that the ground state of ${}^{15}$O is determined by the $p^{14}$N${}^{\ast }$ channel with excited ${}^{14}$N${}^{\ast }$ cluster, which immediately allowed us to correctly describe order of values of the experimental $S$-factor for capture to this state. Taking into account these results, the total $S$-factor of the proton capture on ${}^{14}$N and the reaction rates to the ground and five excited states of ${}^{15}$O were determined at temperatures of 0.01$T_9$ to 10$T_9$. The parametrization of the total reaction rate with a simple form is performed, which allows as to obtain ${\chi }^2$ equal to 0.06 with 5% errors of the calculated rate.

The structure of exotic nuclei sheds new light on the linkage of the nuclear structure to the nucleonic interaction. The self-consistent mean-field (SCMF) theories are useful to investigate this linkage, which are applicable to many nuclei covering almost the whole range of the nuclear chart without artificial truncation of model space. For this purpose, it is desired to develop effective interaction for the SCMF calculations well connected to the bare nucleonic interaction. Focusing on ground-state properties, I show the results of SCMF calculations primarily with the Michigan-three-range-Yukawa (M3Y)-type semi-realistic interaction, M3Y-P6 and M3Y-P6a to be precise, and discuss in detail how the nucleonic interaction affects the structure of nuclei including those far off the $\beta$-stability. The central channels of the effective interaction are examined by the properties of the infinite nuclear matter up to the spin dependence and the isospin dependence. While experimental information of the infinite matter is obtained by extrapolating systematic data on finite nuclei in principle, it is not easy to constrain the spin dependence and the isospin dependence without connection to the bare nucleonic interaction. The noncentral channels play important roles in the shell structure of the finite nuclei. The tensor force is demonstrated to affect $Z$- or $N$-dependence of the shell structure and the magic numbers, on which the spin–isospin channel in the central force often acts cooperatively. By using the M3Y-P6 interaction, the prediction of magic numbers is given in a wide range of the nuclear chart, which is consistent with almost all the available data. In relation to the erosion of magic numbers in unstable nuclei, effects of the tensor force on the nuclear deformation are also argued, being opposite between nuclei at the $\ell s$- and the $jj$-closed magicities. Qualitatively consistent with the $3N$-force effect on the $\ell s$-splitting suggested from the chiral effective field theory, the density-dependent LS channel, which is newly introduced in M3Y-P6a, reproduces the observed kinks in the differential charge radii at the $jj$-closed magic numbers and predicts anti-kinks at the $\ell s$-closed magic numbers. The pairing correlation has significant effects on the halos near the neutron drip line. A new mechanism called “unpaired-particle haloing” is disclosed.

We review the status as regards to the existence of three- and four-body bound states made of neutrons and $\mathrm{\Lambda }$ hyperons. For interesting cases, the coupling to neutral baryonic systems made of charged particles of different strangeness has been addressed. There are strong arguments showing that the $\mathrm{\Lambda }nn$ system has no bound states. $\mathrm{\Lambda }\mathrm{\Lambda }nn$ strong stable states are not favored by our current knowledge of the strangeness $-1$ and $-2$ baryon–baryon interactions. However, a possible ${\mathrm{\Xi }}^{-}t$ quasibound state decaying to $\mathrm{\Lambda }\mathrm{\Lambda }nn$ might exist in nature. Similarly, there is a broad agreement about the nonexistence of $\mathrm{\Lambda }\mathrm{\Lambda }n$ bound states. However, the coupling to $\mathrm{\Xi }NN$ states opens the door to a resonance above the $\mathrm{\Lambda }\mathrm{\Lambda }n$ threshold.

In this study, a systematic analysis is made on the ${}^{22}$Ne nucleus. First, using different theoretical approaches, we show eight density distributions for the ${}^{22}$Ne nucleus. For there densities, we obtain the elastic scattering angular distributions of ${}^{22}$Ne by ${}^{12}$C and ${}^{13}$C targets. Then, to offer alternative nuclear potentials in explaining nuclear interactions related to ${}^{22}$Ne projectile, we calculate the elastic scattering cross-sections of ${}^{22}\mathrm{\text{Ne}}+{}^{12}$C and ${}^{22}\mathrm{\text{Ne}}+{}^{13}$C reactions by using six different nuclear potentials. Finally, we investigate cluster structures of the ${}^{22}$Ne nucleus via a simple cluster approach. We compare the calculated elastic scattering angular distributions with the experimental data.

We study the vorticity patterns in relativistic heavy ion collisions with respect to the collision energy. The collision energy is related to the chemical potential used in the thermal — statistical models that assume approximate chemical equilibrium after the relativistic collision. We use the multiphase transport model (AMPT) to study the vorticity in the initial parton phase as well as the final hadronic phase of the relativistic heavy ion collision. We find that as the chemical potential increases, the vortices are larger in size. Using different definitions of vorticity, we find that vorticity plays a greater role at lower collision energies than at higher collision energies. We also look at other effects of the flow patterns related to the shear viscosity at different collision energies. We find that the shear viscosity obtained is almost a constant with a small decrease at higher collision energies. We also look at the elliptic flow as it is related to viscous effects in the final stages after the collision. Our results indicate that the viscosity plays a greater role at higher chemical potential and lower collision energies.

In this paper, the possible mechanisms, which are responsible for the production of fast target fragments (gray particles with energy 26 up to 400MeV) that were emitted from the interactions of ${}^{32}$S nucleus with emulsion nuclei at energy 3.7AGeV, are studied by the pseudorapidity distribution. The angular distribution of the fast protons ($g$-particles) emitted in the interactions of ${}^{32}$S-Em at 3.7AGeV is nicely described by exp (0.96 cos $𝜃)$, which was observed in proton-induced interactions up to incident energies of 800GeV. The pseudorapidity distributions of the produced $g$-particles were investigated in order to study the characteristics of the emitted system of $g$-particles for different target sizes (CNO, Em and AgBr groups of events). In all cases, the pseudorapidity distributions were parametrized using Gaussian fits. The temperature of the system emitting $g$-particles (hot system) is predicated in the light of the proposed statistical model to be $T\approx 60$MeV.

A possibility of a quark spin polarization originating from a pseudovector condensate is investigated in the three-flavor Nambu–Jona–Lasinio model with the Kobayashi–Maskawa–’t Hooft interaction which leads to flavor mixing. It is shown that a pseudovector condensate related to the strange quark easily occurs compared with pseudovector condensate related to light quarks. Further, it is shown that the pseudovector condensate related to the strange quark appears at a slightly small chemical potential by the effect of the flavor mixing due to the Kobayashi–Maskawa–’t Hooft interaction.

The main purpose of this paper is to rigorously establish the Strutinsky method from the least squares principle. Thus, it is the mathematical basis of this method (aspect often neglected) which is revisited in an extensive way. Some formulas previously given without demonstration or in a simplified way are set out here with all the details. In this respect, the most important mathematical properties of the averaging functions are also established in this paper. When some conditions are met, it turns out that Strutinsky’s method is nothing more than a polynomial moving average of the semi-classical level density.