Low-mass dileptons at the CERN-SpS: evidence for chiral restoration?
R. Rapp1 - J. Wambach2
1 Department of Physics and Astronomy, State University of New York, Stony Brook, NY
11794-3800, USA
2 Institut für Kernphysik, TU Darmstadt, Schlossgartenstr. 9, 64289 Darmstadt, Germany
Received: 30 September 1999 Communicated by B. Povh
Abstract
Using a rather complete description of the in-medium
spectral function - being constrained by various independent
experimental information - we calculate pertinent
dilepton production rates from hot and dense hadronic matter.
The strong broadening of the
resonance entails a
reminiscence to perturbative 
annihilation rates
in the vicinity of the phase boundary.
The application to dilepton observables
in Pb(158AGeV)+Au collisions - incorporating recent information on the
hadro-chemical composition at CERN-SpS energies - essentially supports
the broadening scenario. Possible implications for the nature of
chiral symmetry restoration are outlined.
PACS
12.40.Vv Vector-meson dominance -
21.65.+f Nuclear matter
Copyright Springer-Verlag
