Dileptons from the strongly-interacting Quark-Gluon Plasma within the Parton-Hadron-String-Dynamics (PHSD) approach

TL;DR

This paper investigates dilepton production in heavy-ion collisions using the PHSD transport approach, revealing the roles of vector meson broadening and off-shell quark-antiquark annihilation in the quark-gluon plasma.

Contribution

It introduces a detailed microscopic model that reproduces experimental dilepton spectra, highlighting the importance of nonperturbative QGP effects.

Findings

Low mass dilepton spectra match data with vector meson broadening.

Intermediate mass spectra are dominated by off-shell quark-antiquark annihilation.

Reproduces the softening of the mT spectra at intermediate masses.

Abstract

Dilepton production in In+In collisions at 158 AGeV is studied within the microscopic Parton-Hadron-Strings Dynamics (PHSD) transport approach, which is based on a dynamical quasiparticle model (DQPM) matched to reproduce lattice QCD results in thermodynamic equilibrium. A comparison to the data of the NA60 Collaboration shows that the low mass dilepton spectra are well described by including a collisional broadening of vector mesons, while the spectra in the intermediate mass range are dominated by off-shell quark-antiquark annihilation in the nonperturbative QGP. In particular, the observed softening of the mT spectra at intermediate masses is reproduced.