Probing the early-time dynamics of relativistic heavy-ion collisions with electromagnetic radiation

Understand

Using 3+1D viscous relativistic fluid dynamics, we show that electromagnetic probes are sensitive to the initial conditions and to the out-of-equilibrium features of relativistic heavy-ion collisions.

• Within the same approach, we find that hadronic observables show a much lesser sensitivity to these aspects.
• We conclude that electromagnetic observables allow access to dynamical regions that are beyond the reach of soft hadronic probes.