Mass shift and width broadening of ρ-mesons produced in heavy ion collisions

The mass shift Δm_ρ and width broadening ΔΓ_ρ of ρ-mesons produced in heavy ion collisions is estimated using general formulae which relate the in-medium mass shift of a particle to the real part of the forward scattering amplitude Re f(E) of this particle on constituents of the medium and ΔΓ to the corresponding cross section. It is found that the mass increases by some tens of MeV but, more importantly, the width becomes large, increasing by several hundred MeV at beam energies of a few GeV·A and by twice that amount at beam energies of about a hundred GeV·A. Received: 28 July 1998