Abstract

A novel attempt has been made to probe the QCD phase boundary by using the experimental data for transverse momenta of phi mesons produced in nuclear collisions at AGS, SPS and RHIC energies. The data are confronted with simple thermodynamic expectations and lattice QCD results. The experimental data indicate a first-order phase transition, with a mixed phase stretching the energy density between similar to 1 and 3.2 GeV/fm(3) corresponding to SPS energies.