Dresden 2013 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 74: Schwerionenkollisionen und QCD Phasen
HK 74.5: Talk
Thursday, March 7, 2013, 18:00–18:15, HSZ-201
Off-equilibrium photon production during the chiral phase transition — •Frank Michler1, Hendrik van Hees1,2, Dennis Dean Dietrich1, Stefan Leupold3, and Carsten Greiner1 — 1Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Straße 1, D-60438 Frankfurt, Germany — 2Frankfurt Institute for Advanced Studies (FIAS), Ruth-Moufang-Straße 1, D-60438 Frankfurt, Germany — 3Institutionen för fysik och astronomi, Uppsala Universitet, Box 516, 75120 Uppsala, Sweden
We investigate the photon emission arising from the chiral mass shift
during the chiral phase transition in the early stage of ultrarelativistic
heavy-ion collisions. As this mass shift leads the spontaneous creation of quark-antiquark pairs and thus
contributes to the formation of the quark-gluon plasma, our
investigations are relevant in the context of finite lifetime effects on
the photon emission from the latter. Earlier investigations on this
topic were accompanied by a divergent vacuum contribution and a non-integrability
of the remaining contributions in the ultraviolet domain. In contrast to these
investigations, we do not consider the photon numbers at finite times
but for free asymptotic states obtained by an adiabatic switching of the
electromagnetic interaction according to the Gell-Mann and Low theorem.
This approach eliminates possible unphysical vacuum contributions and
leads to photon spectra integrable in the UV domain. It is emphasized
that the consideration of free asymptotic states is indeed crucial to
obtain such physically reasonable results.
Supported by Land Hessen and HGS-HIRe.