$\rho$ - meson spectral function in hot nuclear matter

TL;DR

This paper investigates the $ ho$-meson spectral function in hot nuclear matter using quantum hadrodynamics and chiral models, analyzing how nucleon loops and different approximations affect the spectral properties.

Contribution

It provides a comparative analysis of the $ ho$-meson spectral function in different theoretical frameworks and approximations, highlighting the impact of nucleon loops and polarization effects.

Findings

Nucleon loops significantly alter the spectral function.

RHA causes a larger mass drop and shifts spectral strength to lower masses.

Spectral function is sharper with nucleon-antinucleon polarization in RHA.

Abstract

We study the $\rho$-meson spectral function in hot nuclear matter by taking into account the isospin-symmetric pion and the nucleon loops within the quantum hadrodynamics (QHD) model as well as using an effective chiral SU(3) model. The spectral function of the $\rho$ meson is studied in the mean field approximation (MFA) as well as in the relativistic Hartree (RHA) approximation. The inclusion of the nucleon loop considerably changes the $\rho$-meson spectral function. Due to a larger mass drop of $ \rho $ meson in the RHA, it is seen that the spectral function shifts towards the low invariant mass region, whereas in the MFA the spectral function is seen to be slightly shifted towards the high mass region. Moreover, while the spectral function is observed to be sharper with the nucleon-antinucleon polarization in RHA, the spectral function is seen to be broader in the MFA.