Speaker
Description
We present a newly developed hybrid hadronic transport + hydrodynamics geared towards heavy ion collisions (HICs) at low to intermediate beam energies, and report on the resulting excitation function of dileptons. In this range of energies, covered by the STAR Beam Energy Scan program and the future CBM experiment at FAIR, it is unclear how to best decribe the medium evolution. At which beam energy is hydrodynamics necessary? How should it be initialized? The electromagnetic radiation in a HIC is heavily dependent on the cumulative emission throughout the expansion, so these questions can be resolved by comparing dilepton observables in different model calculations.
In this work, we propose a dynamic approach to fluidizing hadrons in state-of-the-art evolutions of intermediate beam energy HICs, based on the local energy density. This provides a natural core-corona separation, in contrast to commonly employed initalizations based on a constant proper time. In the presence of a first-order phase transition, the dilepton yield is greatly enhanced, which can be seen in the dilepton excitation function. Moreover, we highlight the need for event-by-event initial conditions compared to smooth averaged profiles, since hotspots account for a significant part of the dilepton spectra.
| Category | Theory |
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