Critical Scattering and Two Photon Spectra for a Quark/Meson Plasma

Abstract

At the Mott transition of a quark/meson plasma, mesons become unbound. This leads to the effect of critical scattering, which is studied by investigating photon pair production due to the process $q\bar{q}\to \gamma \gamma$. This process can proceed either via direct annihilation or via the formation of a mesonic resonance. It is shown that the latter channel leads to an enhancement of photon pairs with invariant mass equal to the thermal pion mass. The size of this effect measures the time the temperature stays near the Mott temperature during the evolution. It is particularly pronounced for a first order phase transition. The ${\pi }^0\to \gamma \gamma$ decay gives a strong background contribution and may make the observation of critical scattering in two-photon spectra of present day heavy ion collision experiments difficult.

23 Pages Revtex, 6 Postscript Figures

References in corpus (1)

• A Numerical Study of an Expanding Plasma of Quarks in a Chiral Model

Cited by in corpus (7)

• Optimized Perturbation Theory at Finite Temperature
• Excess low energy photon pairs from pion annihilation at the chiral phase transition
• Inertial mechanism: dynamical mass as a source of particle creation
• Spectral functions in the sigma-channel near the critical end point
• Quark scattering off quarks and hadrons
• Isentropic thermodynamics and scalar-mesons properties near the QCD critical end point
• Chiral symmetry breaking in hot matter