Low mass dimuons within a hybrid approach

TL;DR

This paper investigates low mass dilepton emissions in heavy-ion collisions using a hybrid model combining transport and hydrodynamics, focusing on the excess observed at SPS energies and analyzing contributions from different collision stages.

Contribution

It introduces a hybrid approach to study dilepton production, highlighting the relative roles of equilibrium and non-equilibrium emission stages in heavy-ion collisions.

Findings

Enhanced dilepton emission in the low mass region compared to long-lived hadron decays.

Significant contributions from both equilibrium and non-equilibrium stages.

Insights into the origin of the dilepton excess observed at SPS energies.

Abstract

We analyse dilepton emission from hot and dense hadronic matter using a hybrid approach based on the Ultrarelativistic Quantum Molecular Dynamics (UrQMD) transport model with an intermediate hydrodynamic stage for the description of heavy-ion collisions at relativistic energies. Focusing on the enhancement with respect to the contribution from long-lived hadron decays after freeze-out observed at the SPS in the low mass region of the dilepton spectra (often referred to as "the excess"), the relative importance of the emission from the equilibrium and the non-equilibrium stages is discussed.