Bonn 2020 – wissenschaftliches Programm
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HK 56.7: Vortrag
Freitag, 3. April 2020, 12:45–13:00, J-HS F
Probing the evolution of heavy-ion collisions using direct photon interferometry — •Nicole Löher — Physikalisches Institut, Universität Heidelberg
A measurement of Hanbury-Brown Twiss (HBT) correlations of direct photons in nucleus-nucleus collisions offers an experimental tool to discriminate between different sources of photon enhancement. Unfortunately the statistics recorded so far at the ALICE experiment at the LHC was not sufficient for such a measurement, but the expected statistics in the upcoming high-luminosity LHC runs could lead to a significant signal. In order to demonstrate this, a feasibility study has been carried out in which two different photon sources in addition to the yields from standard hydrodynamical simulations are investigated. First a photon enhancement near the pseudo-critical temperature Tc ≈ 155 MeV using a phenomenological ansatz and second additional photons, which are produced from the early pre-equilibrium stage, are discussed. For both scenarios the correlators for relative momenta qout, qside and qlong for different transverse pair momenta KT are determined. Among the three directions the longitudinal correlation is the most sensitive to different photon sources. The performed study led to the conclusion that, considering only statistical uncertainties, the detection of 1010 heavy ion events could lead to a measurement of the HBT correlations for KT < 1 GeV which is statistically significant.