The phi meson at high temperatures and densities

TL;DR

This paper investigates how the spectral properties of the phi meson change in hot nuclear matter, finding a slight mass shift but a significant increase in width due to medium effects.

Contribution

It provides a model-independent calculation of the phi meson spectral density at high temperatures and densities using experimental scattering data and dispersion relations.

Findings

Spectral peak shifts slightly from vacuum position.

Width of the phi meson increases significantly in medium.

Spectral modifications are constrained by experimental data.

Abstract

The spectral density of the phi meson in a hot bath of nucleons and pions is calculated by relating the vector meson self-energy to the forward scattering amplitude, which is constrained by experimental data. Dispersion techniques are used to verify the relationship between real and the imaginary parts of the in-medium self energy. The position of the spectral peak of the phi meson is found to be shifted from its vacuum position by only a small amount, but its width is considerably increased.