PaperPanorama

Nuclear Theory·nucl-th

Thursday·April 24, 2025

6 papers2 primary·4 cross-listed

  1. 01

    Energy Rates Due to Weak Decay Rates of Vanadium Isotopes in Stellar Environment

    Ramoona Shehzadi🇵🇰 · Jameel-Un Nabi🇵🇰 · Huma Ali🇵🇰

    The neutrino cooling and gamma heating rates are considered as an important input needed to study the final phases of the evolution of high-mass stars. The weak-interaction mediated processes, namely the -decay and electron capture, significantly change the lepton to baryon ratio and accelerate the contraction of the core. The emission of resulting neutrinos/antineutrinos tends to cool the stellar core. On the other hand, gamma rays are produced because of electron capture and -decay to excited states in daughter nuclei. These gamma rays heat the core and contribute to an increase of entropy which may cause convection to occur. In the present work, the weak-interaction heating and cooling rates on a chain of twenty-two isotopes of vanadium having mass in the range have been estimated using the proton-neutron quasiparticle random phase approximation theory. The rates have been computed for the temperature ranging from ()\;K and for the density range ()\;g/cm. Our calculated neutrino energy loss rates have also been compared with the previously reported rates calculated using other theoretical models. At high stellar temperatures, our rates are larger by 1-2 orders of magnitude as compared to previous results.

    nucl-thAstrophys.Space Sci.(2020)·3 citations
  2. 02

    Impact of spin polarization on the QCD equation of state

    De-Xian Wei🇨🇳

    Spin polarization provides a novel probe of the rotational properties of the quark-gluon plasma formed in relativistic heavy-ion collisions. This work investigates the equation of state, particularly its transport and thermodynamic coefficients in noncentral O+O collisions, employing a parton distribution function that incorporates spin polarization induced by thermal vorticity. Within a kinetic theory framework, one finds that the magnitude of the squared speed of sound () is only weakly modified by spin polarization, whereas the specific shear viscosity (), specific bulk viscosity (), and mean free path () show substantial changes. When spin polarization is included, both and develop a nonmonotonic dependence on the collision energy, with an inflection point near GeV, corresponding to an average parton chemical potential of GeV. These results suggest that spin polarization may serve as a useful probe for constraining the effective equation of state of QCD matter.

    nucl-thPRC(2026)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE