Semi-central In-In collisions and Brown-Rho scaling

Abstract

In connection with the claim made at the Quark Matter 2005 Conference that the Brown-Rho scaling is ruled out by NA60 data we consider dimuon production from semi-central In+In collisions in a full dynamical model. It is shown that if only a modification of the density-dependent $\rho$-mass is allowed, the maximum of dimuon invariant mass spectra is only slightly below experimental one. The additional inclusion of the temperature-dependent modification factor shifts the spectrum maximum toward lower invariant masses making calculation results incompatible with data. A further study is needed to disentangle the BR dropping $\rho$ mass scaling and strong broadening.

3 pages, 4 figures (the title is changed, a new curve is added in Fig. 4., minor modifications in the text and abstract)