On Hydrodynamical Description of Thermal Photons

Abstract

The WA98 collaboration in the CERN SPS has reported an excess of photons over those originating from the decays of final hadrons in the lead-lead collisions. These photons can originate either from primary interactions of partons from colliding nuclei or from secondary interactions among produced particles. Photons produced in the secondary interactions, often called thermal photons, can be calculated by using thermal production rates and equilibrium hydrodynamics for the evolution of the expanding matter. I will review the main features of hydrodynamical studies for the WA98 data. The data can be reproduced both with or without a phase transition to the QGP, but high initial temperature, over the values predicted for the phase transition temperature, is required by the data. I will also show a prediction for the photon excess for central gold-gold collisions at the Brookhaven RHIC collider. In this prediction, the initial state for the hydrodynamical expansion is obtained from a perturbative QCD calculation.

9 pages, 6 figures, Contribution to Quark Matter 2002, Nantes, France, July 18-24, 2002

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Cited by in corpus (8)

• Hydrodynamic Models for Heavy Ion Collisions
• RHIC-tested predictions for low-$p_T$ and high-$p_T$ hadron spectra in nearly central Pb+Pb collisions at the LHC
• Wess-Zumino-Witten action and photons from the Chiral Magnetic Effect
• Quark-Gluon Matter
• Elliptic flow of thermal photons in heavy-ion collisions at Relativistic Heavy Ion Collider and Large Hadron Collider
• Relevance of baseline hard proton-proton spectra for high-energy nucleus-nucleus physics
• The Vector Probe in Heavy-Ion Reactions
• Electromagnetic probes