A coarse-graining approach for dilepton production at SPS energies

Understand

Coarse-grained output from transport calculations is used to determine thermal dilepton emission rates by applying medium-modified spectral functions from thermal quantum field theoretical models.

• By averaging over an ensemble of events generated with the UrQMD transport model, we extract the local thermodynamic properties at each time step of the calculation.
• With an equation of state the temperature $T$ and chemical potential $\mu_{\mathrm{B}}$ can be determined.
• The approach goes beyond simplified fireball models of the bulk-medium evolution by treating the full (3+1)-dimensional expansion of the system with realistic time and density profiles.