Temperature effects on nuclear pseudospin symmetry in the Dirac-Hartree-Bogoliubov formalism

TL;DR

This study investigates how nuclear temperature influences pseudospin symmetry in tin isotopes using finite temperature Dirac-Hartree-Bogoliubov calculations, revealing that higher temperatures improve pseudospin symmetry due to increased surface diffuseness.

Contribution

It extends previous zero-temperature studies by analyzing temperature effects on pseudospin symmetry within a self-consistent finite temperature relativistic framework.

Findings

Pseudospin symmetry improves with increasing temperature.

Surface diffuseness of the nuclear potential is the main factor affecting pseudospin splitting.

Dynamical pseudospin symmetry persists at finite temperatures.

Abstract

We present finite temperature Dirac-Hartree-Bogoliubov (FTDHB) calculations for the tin isotope chain to study the dependence of pseudospin on the nuclear temperature. In the FTDHB calculation, the density dependence of the self-consistent relativistic mean fields, the pairing, and the vapor phase that takes into account the unbound nucleon states are considered self-consistently. The mean field potentials obtained in the FTDHB calculations are fit by Woods-Saxon (WS) potentials to examine how the WS parameters are related to the energy splitting of the pseudospin pairs as the temperature increases. We find that the nuclear potential surface diffuseness is the main driver for the pseudospin splittings and that it increases as the temperature grows. We conclude that pseudospin symmetry is better realized when the nuclear temperature increases. The results confirm the findings of previous works using RMF theory at $T=0$, namely that the correlation between the pseudospin splitting and the parameters of the Woods-Saxon potentials implies that pseudospin symmetry is a dynamical symmetry in nuclei. We show that the dynamical nature of the pseudospin symmetry remains when the temperature is considered in a realistic calculation of the tin isotopes, such as that of the Dirac-Hartree-Bogoliubov formalism.