Nuclear Theory·nucl-th

Wednesday·January 17, 2024

26 papers—9 primary·17 cross-listed

01
[Submitted on 14 Jan 2024]
Folding potential with modern nuclear density functionals and application to 16O+208Pb reaction
Kyoungsu Heo · Hana Gil · Ki-Seok Choi · K. S. Kim · Chang Ho Hyun · W. Y. So
Double folding potential is constructed using the M3Y interaction and the matter densities of the projectile and target nuclei obtained from four microscopic energy density functional (EDF) models. The elastic scattering cross sections for the 16O+208Pb system are calculated using the optical model with the double folding potentials of the four EDF models. We focus on the correlation between the matter densities and the behavior the double folding potential and the elastic scattering cross sections. First, the matter and charge densities are examined by comparing the results of the four EDF models. There is a slight difference in the density in the internal region, but it is negligible in the outer region. Next, we calculate the double folding potential with the matter densities obtained from the four EDF models. Differences between the models are negligible in the outer region, but the potential depth in the internal region shows model dependence, which can be understood from the behavior of matter densities in the internal region. Another point is that the double folding potential is shown to be weakly dependent on the incident energy. Finally, the elastic scattering cross sections have no significant model dependence except for the slight difference in the backward angle.
Comments:
17 pages, 13 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2401.07219 [pdf]
PRC(2024)·0 citations
02
[Submitted on 14 Jan 2024]
Isospin splitting of the Dirac mass probed by the relativistic Brueckner-Hartree-Fock theory in the full Dirac space
Pianpian Qin · Qiang Zhao · Hui Tong · Chencan Wang · Sibo Wang
The isospin splitting of the Dirac mass obtained with the relativistic Brueckner-Hartree-Fock (RBHF) theory is thoroughly investigated. From the perspective in the full Dirac space, the long-standing controversy between the momentum-independence approximation (MIA) method and the projection method on the isospin splitting of the Dirac mass in asymmetric nuclear matter (ANM) is analyzed in detail. We find that, the \textit{assumption procedure} of the MIA method, which assumes that the single-particle potentials are momentum independent, is not a sufficient condition that directly leads to the wrong sign of the isospin splitting of the Dirac mass, while the \textit{extraction procedure} of the MIA method, which extracts the single-particle potentials from the single-particle potential energy, leads to the wrong sign. By approximately solving the set of equations involved in the \textit{extraction procedure}, a formal expression of the Dirac mass is obtained. The wrong isospin splitting of the Dirac mass is mainly caused by that the \textit{extraction procedure} forcely assumes the momentum dependence of the single-particle potential energy to be a quadratic form where the strength is solely determined by the constant scalar potential.
Comments:
13 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2401.07318 [pdf]
Nucl.Sci.Tech.(2025)·8 citations
03
[Submitted on 15 Jan 2024]
Weak magnetic effect in quark-gluon plasma and local spin polarization
Jing-An Sun🇨🇳 · Li Yan🇨🇳
We propose the weak magnetic effect, which emerges in quark-gluon plasma close to local thermal equilibrium as the dissipative correction to the quark phase space distribution function, as a novel contribution to the observed Lambda hyperon local spin polarization. With a finite field strength, which is consistent with previous estimate of the magnetic field in heavy-ion collisions, one is able to explain the experimentally observed Lambda local spin polarization through all centrality classes. Moreover, the weak magnetic effect plays an unambiguous role in the ordering between the second-order and the third-order modulations of the Lambda local spin polarization in experiments.
Comments:
Typos corrected
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2401.07458 [pdf]
CPC(2025)·10 citations
04
[Submitted on 15 Jan 2024]
Calculation of Fission Fragment Yields for thermal neutron reaction of $^{239}$ Pu
Futoshi Minato
Fission fragment yield evaluation in the past has been done mainly by considering independent and cumulative fission yields. In addition to them, the fission fragment yields are related to various observables such as total kinetic energy, prompt fission neutron, decay heats, etc. Various improvements were carried out in the fission fragment yield evaluation of JENDL-5, however it did not consider correlations between such fission observables and fragment yields. A new evaluation including fission observables is thus required for next generation of evaluated data. We recently developed a new calculation system using CCONE code to calculate fission fragment yields. This calculation system enables us to compare various fission observables with the experimental data simultaneously. In this work, we calculated thermal-induced fission of 239Pu. We present the result of prompt fission neutrons, decay heats, and delayed neutrons
Comments:
6 pages, 2 figures, submitted to the Proceedings of Joint Symposium on Nuclear Data and PHITS in 2023
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2401.07545 [pdf]
0 citations
05
[Submitted on 15 Jan 2024]
Correlation of the hyperon potential stiffness with hyperon constituents in neutron stars and heavy-ion collisions
Si-Na Wei🇨🇳 · Zhao-Qing Feng🇨🇳 · Wei-Zhou Jiang🇨🇳
The breaking of SU(6) symmetry to a more general flavor SU(3) symmetry could serve as a potential explanation for the "hyperon puzzle" of neutron stars by adjusting the hyperon potentials. Specifically, when the soft relativistic mean-field (RMF) $Λ$ hyperon potentials fall within the domains of chiral SU(3) interactions NLO13 with two-body forces, the maximum mass of neutron stars is expected to be lower than 2.0 $M_{⊙}$ , whereas it can exceed $2.0 M_{⊙}$ if the RMF $Λ$ hyperon potentials are sufficiently stiff to be consistent with those from chiral SU(3) interactions NLO13 with three-body forces. In our investigation involving these two types of $Λ$ hyperon potentials, we explore how the hyperon yields and flows are affected in heavy-ion collisions. We find that the inclusion of hyperon potentials results in better agreement of the $Λ$ directed flows with data but without clear differentiation in the stiffness of the hyperon potentials. Similarly negligent is the disparity in the rapidity distributions of the $Λ$ collective flows predicted by the stiff and soft hyperon potentials. In contrast, the $Λ$ collective flows beyond the central rapidity region turn out to be sensitive to the stiffness of the RMF equation of state (EOS) with the preference of a soft RMF EOS to a stiff one. Notably, the transverse momentum distributions of $Λ$ hyperon production are sensitive to both the stiffness of the RMF EOS and $Λ$ hyperon potential at high transverse momenta.
Comments:
8 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2401.07653 [pdf]
PLB(2024)·14 citations
06
[Submitted on 15 Jan 2024]
Radial Oscillations of Hybrid Stars and Neutron Stars including Delta baryons: The Effect of a Slow Quark Phase Transition
Ishfaq Ahmad Rather🇩🇪 · Kauan D. Marquez🇵🇹 · Betania C. Backes🇬🇧 · Grigoris Panotopoulos🇨🇱 · Ilidio Lopes🇵🇹
We study radial oscillations of hybrid neutron stars composed of hadronic external layers followed by a quark matter core. We employ a density-dependent relativistic mean-field model including hyperons and $Δ$ baryons to describe hadronic matter, and a density-dependent quark model for quark matter. We obtain the ten lowest eigenfrequencies and the corresponding oscillation functions of N, N+ $Δ$ , N+H, and N+H+ $Δ$ equations-of-state with a phase transition to the quark matter at 1.4 and 1.8 $M_{⊙}$ , focusing on the effects of a slow phase transition at the hadron-quark interface. We observe that the maximum mass is reached before the fundamental mode's frequency vanishes for slow phase transitions, suggesting that some stellar configurations with higher central densities than the maximum mass remain stable even when they undergo small radial perturbations. Future gravitational wave detectors and multi-messenger astronomy, complemented by robust microscopic models enabling exploration of various neutron star compositions, including hyperon content, are anticipated to impose precise limitations on the equation of state of baryonic matter under high-density conditions.
Comments:
31 pages, 9 figures, 5 tables: updated version accepted for publication in JCAP
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2401.07789 [pdf]
JCAP(2024)·23 citations
07
[Submitted on 16 Jan 2024]
Shell effects on the drift and fluctuation in multinucleon transfer reactions
Zehong Liao · Zepeng Gao · Yu Yang · Jun Su · Long Zhu
This study employs the dinuclear system model (DNS-sysu) to investigate drift and fluctuation mechanisms in 136Xe + 209Bi collisions above the Coulomb barrier. The DNS-sysu model demonstrated its effectiveness in providing reasonable descriptions of drift and fluctuation dynamics for the multinucleon transfer reaction at low energies. We observe temperature-induced changes in the shell effect, impacting nucleon transfer. At higher energies, the weakening constraint of the potential energy surface leads to a reversal in the evolution direction. Additionally, the consideration of shell corrections notably affects fragment distribution at low energies but diminishes for high-energy conditions. This research provides valuable insights into understanding the macroscopic manifestation of nucleon transfer in the multinucleon transfer reaction.
Comments:
8 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2401.08319 [pdf]
PRC(2024)·11 citations
08
[Submitted on 16 Jan 2024]
Constraints on the isovector properties of finite nuclei from neutron stars observations
M. Divaris · A. Kanakis-Pegios · Ch.C. Moustakidis
The nuclear symmetry energy plays important role on the structure of finite nuclei as well as on the bulk properties of neutron stars. However, its values at high densities are completely uncertain and the corresponding experimental data have a large error. One possibility to determine or at least estimate the values at high densities is with the help of neutron star observations. Recently, observations of gravitational waves from merging processes of binary neutron star systems provide useful information on both their radius and tidal deformability, quantities directly related to the symmetry energy. In this work, an attempt is made in this direction, namely to see how recent observations can help to constrain the structure of finite nuclei. In particular, in the present study we parameterize the equation of state which describes the asymmetric and symmetric nuclear mater with the help of the parameter $η = (K_{0} L^{2})^{1/3}$ , where $K_{0}$ is the incompressibility and $L$ the slope parameter. The parameter $η$ is a regulator of the stiffness of the equation of state. We expect that the values of $η$ affect both the properties of finite nuclei as well as of the neutron star properties (where the role of the isovector interaction plays important role). It is natural to expect that constraints, via the parameter $η$ on finite nuclei will imply constraints on the neutron star properties and vice versa. In view of the above statements we propose a simple but self-consistent method to examine simultaneously the effects of the parameter $η$ on the properties of finite nuclei and neutron stars. We found constraints on the latter systems via combination by the recent experiments (PREX-2) and observational data found by the detectors Ligo and Virgo.
Comments:
11 pages, 6 figures. Any comments are welcome
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)
arXiv:
2401.08322 [pdf]
PRC(2024)·9 citations
09
[Submitted on 16 Jan 2024]
Exploring Radial Oscillations in Slow Stable and Hybrid Neutron Stars
Sayantan Ghosh · Sailesh Ranjan Mohanty · Tianqi Zhao · Bharat Kumar
In the era of gravitational wave astronomy, radial oscillations hold significant potential for not only uncovering the microphysics behind the internal structure but also investigating the stability of neutron stars (NSs). We start by constructing families of static NSs following nucleonic, quarkyonic, and hybrid equations of state and then subject them to radial perturbations in order to explore the stability of these stars. Unlike other literature where the fluid elements are assumed to be in chemical equilibrium, we consider the out-of-equilibrium effects on the chemical composition of fluid elements for the calculation of radial modes. Taking these considerations into account, we observe that the sound speed ( $c_{s}^{2}$ ) and adiabatic index ( $γ$ ) avoid singularities and discontinuities over the equilibrium case. We elucidate the response of the fundamental radial modes by examining the out-of-equilibrium matter distribution scenario, offering insights into its dynamic variations. We also demonstrate that this approach extends the stable branches of stellar models, enabling stars to sustain stable higher-order mass doublets, shedding some light on observation and existence of PSR J0740+6620.
Comments:
Comments and suggestions are welcome
Subjects:
Nuclear Theory (nucl-th); Astrophysics of Galaxies (astro-ph.GA); General Relativity and Quantum Cosmology (gr-qc)
arXiv:
2401.08347 [pdf]
JCAP(2025)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE