Nonequilibrium production of photons via {pi}{sup 0}{r_arrow}2{gamma} in disoriented chiral condensates
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)
- LPTHE, Universite Pierre et Marie Curie (Paris VI), Tour 16, 1er. etage, 4, Place Jussieu, 75252 Paris, Cedex 05 (France)
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)
We study the production of photons via the nonequilibrium relaxation of a disoriented chiral condensate with the chiral order parameter having a large initial amplitude along the {pi}{sup 0} direction. Assuming the validity of the low-energy coupling of the neutral pion to photons via the U{sub A}(1) anomalous vertex, we find that for large initial amplitudes along the {pi}{sup 0} direction photon production is enhanced by parametric amplification. These processes are nonperturbative with a large contribution during the nonequilibrium stages of the evolution and result in a distinct distribution of the produced photons and a polarization asymmetry. For initial amplitudes of the {pi}{sup 0} component of the order parameter between 200 and 400 MeV, corresponding to energy densities between 1 and 12 GeV/fm{sup 3}, we find a peak in the photon distribution at energies between {approx}300 and 600 MeV. We also find polarization asymmetries typically between 5{percent} and 10{percent}. We discuss the potential experimental impact of these results as well as the problems associated with its detection. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 542747
- Journal Information:
- Physical Review, D, Journal Name: Physical Review, D Journal Issue: 7 Vol. 56; ISSN 0556-2821; ISSN PRVDAQ
- Country of Publication:
- United States
- Language:
- English
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