Quasiparticle-vibration coupling effects on nuclear transitions of astrophysical interest

TL;DR

This paper applies the relativistic quasiparticle time-blocking approximation (RQTBA) to study nuclear excitation modes relevant for astrophysics, improving the understanding of nuclear reactions involved in stellar nucleosynthesis.

Contribution

It introduces the RQTBA method for nuclear excitations, incorporating quasiparticle-vibration coupling, and applies it to calculate astrophysically important nuclear transition rates.

Findings

Calculated electric dipole and Gamow-Teller transitions in Sn isotopes.

Provided reaction and decay rates relevant for r-process nucleosynthesis.

Analyzed Gamow-Teller transitions in $^{90}$Zr for stellar evolution modeling.

Abstract

The relativistic quasiparticle time-blocking approximation (RQTBA) is applied to the description of nuclear excitation modes of astrophysical interest. This method is based on the meson-nucleon Lagrangian and goes beyond the standard relativistic quasiparticle random-phase approximation (RQRPA) by treating the coupling between single quasiparticles and collective vibrations of the nucleus. We calculate electric dipole transitions and Gamow-Teller modes in the (p,n) direction in a few Sn isotopes and obtain the rates of (n,$\gamma$) reaction and $\beta^-$-decay processes, which govern the r-process nucleosynthesis, in a unified RQTBA framework. Gamow-Teller transitions in the (n,p) branch, which in principle can serve for the modeling of stellar evolution, are also investigated, and $^{90}$Zr is taken as a study case.