Properties of $\rho$-mesons produced in heavy ion collisions

The mass shift and width broadening of $\rho$-mesons produced in heavy ion collisions is estimated. It is found that the mass increases by some tens of MeV but the width becomes large, increasing by 200 MeV at beam energies of a few GeV$\cdot$A and by twice that amount at beam energies of about a hundred GeV$\cdot$A.