SMuK 2023 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 6: Heavy-Ion Collisions and QCD Phases II
HK 6.2: Vortrag
Montag, 20. März 2023, 17:00–17:15, SCH/A315
Thermal dileptons as a multi-messenger probe of the fireball — •Florian Seck1, T. Galatyuk1,2, R. Rapp3, N. Schwarz1, J. Steinheimer4,5, J. Stroth4,2, and M. Wiest1 — 1Technische Universität Darmstadt — 2GSI, Darmstadt — 3Texas A&M University, College Station, USA — 4Universität Frankfurt — 5FIAS, Frankfurt
As dileptons are radiated from the extreme states of matter created in heavy-ion collisions with negligible final-state interactions, they retain the information imprinted on them at the time of their creation. Multi-differential measurements of dilepton invariant mass, momentum, and angular distributions can therefore serve as a multi-messenger tool to characterize the properties of matter in the interior of the hot and dense fireball. To compute thermal dilepton spectra, we integrate in-medium dilepton rates over the space-time evolution of the collision described by a coarse-graining method of hadronic transport or hydrodynamic simulations. While the general shape of the dilepton invariant mass spectrum probes the baryon density, the slope at moderate masses measures the average temperature reached during the collision. The yield in the low-mass range is related to the fireball lifetime and is enhanced if a significant fraction of the fireball volume crosses a possible first-order phase transition. The analysis of the collective flow and polarization of dileptons can provide additional insights into the space-time evolution of the fireball in the QCD phase diagram and possible changes in the composition of the emitting source.
This work has been supported by: VH-NG-823, Helmholtz Alliance HA216/EMMI, GSI, HFHF, and the DFG through grant CRC-TR 211.