1996/08/23 by C. M. Hung, C. Hung, E. V. Shuryak +1 · 2 citations
Physics and Astronomy · #Annihilation #Excited state #Gluon #Hadron #High-Energy Particle Collisions Research #Meson #Nuclear physics #Order (exchange) #Particle physics #Particle physics theoretical and experimental studies #Phase transition #Physics #Plasma #Production (economics) #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quark–gluon plasma #hep-ph #nucl-th
paper · pdf · doi:10.1103/physrevc.56.453
published as Phys.Rev.C56:453-467,1997 · 34 pages LaTeX, with encapsulated ps figures. WWW home at http://looney.physics.sunysb.edu/~daffy/phd.html One comment and one reference added to appendix
arxiv created 1996/08/23 · openalex publication_date 1997/07/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study the electromagnetic production from highly excited hadronic matter created in heavy ion collisions. The rates include the usual lowest order processes in quark-gluon plasma plus the usual reactions in the hadronic phase, related with \ensuremathρ,a1 mesons. The space-time integration is done using a hydrodynamical model. Conventional qq (\ensuremathπ+\ensuremathπ^\ensuremath-) annihilation in quark-gluon plasma and hadronic phase cannot explain the observed dilepton spectrum, especially that by the CERES experiment at CERN. A decreased \ensuremathρ mass can account for the observed effect, provided it shifts into the region of 0.4--0.5 GeV near the phase transition. In order to test this hypothesis one should also look at the chiral partner of \ensuremathρ, the axial a1 meson: its mass must then behave similarly. Its decay a1\ensuremath→\ensuremathπe+e^\ensuremath- populates the low mass region seen in the same experiment. The results for direct photon production are below the current WA80 experimental bounds, for all variants considered.