IN-MEDIUM MODIFICATION OF RHO-MESONS PRODUCED IN HEAVY-ION COLLISIONS

The mass shift Delta m(rho) and width broadening Delta Gamma(rho) of r ho mesons produced in heavy ion collisions is estimated using a genera l formula which relates the in-medium mass shift of a particle to the real part of the forward scattering amplitude Ref(E) of this particle on constituents of the medium and Delta Gamma to the corresponding cro ss section. It is found that in high energy (E/A greater than or simil ar to 100 GeV) heavy ion collisions the rho width broadening is large and rho (or omega) peak could hardly be observed in e(+)e(-)(mu(+)mu(- )) effective mass distributions. In low energy collisions (E/A similar to a few GeV) a broad (a few hundred MeV) enhancement is expected at the position of the rho peak.