In-medium vector mesons and low mass lepton pairs from heavy ion collisions

TL;DR

This paper investigates how in-medium modifications of rho and omega mesons at finite temperature and density affect low mass dilepton production in heavy ion collisions, showing enhanced yields consistent with experimental data.

Contribution

It provides a comprehensive analysis of mesonic and baryonic loop effects on vector meson spectral functions using thermal field theory, linking these to dilepton yields in heavy ion collisions.

Findings

Significant spectral strength enhancement below rho mass

Enhanced dilepton yield matches NA60 experimental data

In-medium effects are crucial for understanding dilepton production

Abstract

The rho and omega meson self-energy at finite temperature and baryon density have been analysed for an exhaustive set of mesonic and baryonic loops in the real time formulation of thermal field theory. The large enhancement of spectral strength below the nominal rho mass is seen to cause a substantial enhancement in dilepton pair yield in this mass region. The integrated yield after space-time evolution using relativistic hydrodynamics with quark gluon plasma in the initial state leads to a very good agreement with the experimental data from In-In collisions obtained by the NA60 collaboration.