Temperature dependence of nuclear spin-isospin response and beta decay in hot astrophysical environments

Elena Litvinova, Caroline Robin, Herlik Wibowo 2020 Phys. Lett. B 800 135134

A microscopic approach to the proton-neutron nuclear response is formulated in the finite-temperature relativistic nuclear field theory framework. The approach is based on the meson-nucleon Lagrangian of quantum hadrodynamics and advances the relativistic field theory for spin-isospin response beyond the finite-temperature random phase approximation. The dynamical contribution to the in-medium proton-neutron interaction amplitude is described in a parameter-free way by the coupling between the single nucleons and strongly-correlated particle-hole excitations (phonons) within the newly developed finite-temperature formalism. In this framework we investigate temperature dependence of the Gamow-Teller and spin dipole resonances in the closed-shell nuclei 48Ca, 78Ni, and 132Sn. Broader impacts of their temperature dependence are illustrated for the associated beta decay rates and lifetimes of 78Ni and 132Sn in hot astrophysical environments. We found a remarkable sensitivity of the beta decay rates to the enhanced low-energy spin-isospin strength at finite temperature, in particular, to the contribution of the first-forbidden transitions.