Low mass dimuons produced in relativistic nuclear collisions.
The NA60 experiment has measured low mass muon pair production in In-In collisions at 158A GeV with unprecedented precision. We show that these data are reproduced very well by a dynamical model with parameters scaled from fits to measurements of hadronic transverse mass spectra and Hanbury Brown-Twiss correlations in Pb-Pb and Pb-Au collisions at the same energy. The data are consistent with in-medium properties of rho and omega mesons at finite temperature and density as deduced from empirical forward-scattering amplitudes. Inclusion of the vacuum decay of the rho meson after freeze-out is necessary for an understanding of the mass and transverse momentum spectrum of dimuons with M less similar 0.9 GeV/c(2).
Department of Physics, McGill University, 3600 University Street, Montreal, QC, H3A 2T8 Canada.
Jörg
J
Ruppert
Charles
C
Gale
Thorsten
T
Renk
Peter
P
Lichard
Joseph I
JI
Kapusta