Nuclear Theory·nucl-th

Wednesday·November 27, 2024

11 papers—7 primary·4 cross-listed

08
Impact of nuclear mass models on $r$ -process nucleosynthesis and heavy element abundances in $r$ -process enhanced metal-poor stars
Meng-Hua Chen · Li-Xin Li · En-Wei Liang · Ning Wang
Due to the lack of experimental data on extremely neutron-rich nuclei, theoretical values derived from nuclear physics models are essential for the rapid neutron capture process ( $r$ -process). Metal-poor stars enriched by the $r$ -process offer valuable cases for studying the impact of nuclear physics models on $r$ -process nucleosynthesis. This study analyzes four widely used nuclear physics models in detail: Finite-Range Droplet Model, Hartree-Fock-Bogoliubov, Duflo-Zuker, and Weizs $a ¨$ cker-Skyrme (WS4). Theoretical values predicted by the WS4 model are found to be in good agreement with experimental data, with deviations significantly smaller than those predicted by other models. The heavy element abundances observed in $r$ -process enhanced metal-poor stars can be accurately reproduced by $r$ -process nucleosynthesis simulations using the WS4 model, particularly for the rare earth elements. This suggests that nuclear data provided by nuclear physics model like WS4 are both essential and crucial for $r$ -process nucleosynthesis studies.
↳ astro-ph.HEastro-ph.SRnucl-thAstron.Astrophys.(2025)·2 citations
09
Effect of chiral imbalance on the electrical conductivity of hot and dense quark matter using Green-Kubo Method within the 2-flavour gauged NJL model
Snigdha Ghosh🇮🇳 · Nilanjan Chaudhuri🇮🇳 · Sourav Sarkar🇮🇳 · Pradip Roy🇮🇳
The electrical conductivity of hot and dense quark matter is calculated using the 2-flavour gauged Nambu-Jona--Lasinio (NJL) model in the presence of a chiral imbalance quantified in terms of a chiral chemical potential (CCP). To this end, the in-medium spectral function corresponding to the vector current correlator is evaluated employing the real time formulation of finite temperature field theory. Taking the long wavelength limit of the spectral function we extract the electrical conductivity using the Green-Kubo relation. The thermal widths of the quarks/antiquarks that appear in the expression of electrical conductivity are calculated by considering the $2 \to 2$ scattering in the NJL model. The scattering amplitudes containing the polarization functions of the mesonic modes in the scalar and pseudoscalar channels are also evaluated by considering finite value of CCP. We find that the ratio of electrical conductivity to temperature has significant dependence on CCP especially in the low temperature region.
↳ hep-phnucl-thEPJC(2024)·2 citations
10
Constraints on color-flavor locked quark matter in view of the HESS J1731-347 measurement
K. Kourmpetis🇬🇷 · P. Laskos-Patkos🇬🇷 · Ch.C. Moustakidis🇬🇷
Astrophysical observations play a crucial role in understanding the processes within compact stars. A recent study measured the central object in the HESS J1731-347 supernova remnant (SNR), estimating its mass at $M = 0.7 7_{- 0.17}^{+ 0.20} M_{⊙}$ and radius at $R = 10.4 0_{- 0.78}^{+ 0.86} km$ , identifying it as the lightest neutron star ever observed. Conventional models suggest neutron stars form with a minimum gravitational mass of approximately $1.17 M_{⊙}$ , raising the question of whether this object is a typical neutron star or possibly an "exotic" star. To investigate, we utilize the Color-Flavor Locked (CFL) equation of state (EoS), integrating data from the HESS J1731-347 measurement with pulsar observations and gravitational wave detections. Additionally, we construct hybrid EoS by combining the MDI-APR1 (hadronic) and CFL (quark) EoS, introducing a phase transition through Maxwell construction. Our findings reveal that absolutely stable CFL quark matter effectively explains all observed measurements, including the central object of HESS J1731-347, whereas hybrid models incorporating the CFL MIT Bag model cannot account for the masses of the most massive observed pulsars.
↳ astro-ph.HEgr-qcnucl-thHNPS Adv.Nucl.Phys.(2025)·7 citations
11
Dissociation and regeneration of charmonia within microscopic Langevin simulations
Naomi Oei🇩🇪 · Juan M. Torres-Rincon🇪🇸 · Hendrik van Hees🇩🇪 · Carsten Greiner🇩🇪
We present a classical model to study the formation of charmonia, as well as dissociation and regeneration processes of heavy-quark bound states in the quark gluon plasma using Langevin simulations. The charm and anticharm quarks are described as Brownian particles in the background medium of light quarks and gluons and interact among them over a Coulomb-like screened potential to form bound states, which can dissociate again due to interactions with the medium. Box simulations at fixed temperature and volume are used to verify that the system reaches the expected thermal distribution in the equilibrium limit and to test bound state properties. The medium evolution is then parametrized by a boost-invariant fireball. In this configuration, the elliptic flow of charm and anticharm quarks as well as of charmonia is studied at RHIC and LHC energies.
↳ hep-phnucl-thPoS(2025)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Impact of nuclear mass models on r-process nucleosynthesis and heavy element abundances in r-process enhanced metal-poor stars

Effect of chiral imbalance on the electrical conductivity of hot and dense quark matter using Green-Kubo Method within the 2-flavour gauged NJL model

Constraints on color-flavor locked quark matter in view of the HESS J1731-347 measurement

Dissociation and regeneration of charmonia within microscopic Langevin simulations

Affiliations

Impact of nuclear mass models on $r$ -process nucleosynthesis and heavy element abundances in $r$ -process enhanced metal-poor stars