Initial temperature and EoS of quark matter from direct photons

Abstract

The time evolution of the quark gluon plasma created in gold-gold collisions of the Relativistic Heavy Ion Collider (RHIC) can be described by hydrodynamical models. Distribution of hadrons reflects the freeze-out state of the matter. To investigate the time evolution one needs to analyze penetrating probes, such as direct photon spectra. Distributions of low energy photons was published in 2010 by PHENIX. In this paper we analyze a 3+1 dimensional solution of relativistic hydrodynamics and calculate momentum distribution of direct photons. Using earlier fits of this model to hadronic spectra, we compare photon calculations to measurements and find that the initial temperature of the center of the fireball is at least 519+-12 MeV, while for the equation of state we get c_s= 0.36+-0.02.

Talk at the VI Workshop on Particle Correlations and Femtoscopy, Kiev, September 14-18, 2010. 6 pages, 1 figure. This work was supported by the OTKA grant NK73143 and M. Csanad's Bolyai scholarship

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• The QCD equation of state with dynamical quarks
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• Scaling properties of azimuthal anisotropy in Au+Au and Cu+Cu collisions at sqrt(s_NN) = 200 GeV
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Cited by in corpus (7)

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• Excitation function of initial temperature of heavy flavor quarkonium emission source in high energy collisions
• Excitation functions of related temperatures of η and η0 emission sources from squared momentum transfer spectra in high-energy collisions
• Scaling behaviour of $dN/dy$ in high-energy collisions
• Hydrodynamic description of direct photon spectra and elliptic flow in Pb+Pb collisions at LHC
• Oscillating HBT radii and the time evolution of the source - sqrt(s_NN) = 200 GeV Au+Au data analyzed with azimuthally sensitive Buda-Lund hydro model