Rho properties in a hot meson gas

TL;DR

This paper investigates rho meson interactions in a hot meson gas using effective Lagrangians, emphasizing the role of subthreshold resonances and off-shell effects to improve dilepton spectrum predictions.

Contribution

It introduces a self-consistent approach at finite temperature that includes new reactions and off-shell effects, enhancing the understanding of rho meson properties in hot environments.

Findings

Subthreshold resonances significantly influence rho meson properties.

Off-shell effects are crucial for accurate dilepton spectrum calculations.

The approach improves agreement with experimental dilepton production data.

Abstract

Using effective meson Lagrangians we study the interaction of rho mesons in a hot baryon-free system. Various mesonic resonances in direct $s$-channel reactions are investigated employing standard self-energy techniques, including new reactions that have up to now not been considered in a self-consistent approach at finite temperature. The importance of subthreshold resonances, which are readily accounted for through off-shell effects within our framework, is emphasized. Special care is taken in reproducing radiative decay widths, as they provide valuable constraints on the evaluation of dilepton spectra. In particular, we compare our results for dilepton production rates to earlier calculations based on an incoherent summation of individual processes.