The baryon-number density formed in relativistic nuclear collisions, versus the chemical potential of the freeze-out states, is systematically studied on the basis of existing measurements. A remarkable power-law behaviour of the baryon-number susceptibility is found at the SPS, consistent with the existence of a QCD critical point at $\mu_{ B,c}\simeq 214$ MeV, $T_c\simeq 155$ MeV. The equation of state in different asymptotic regimes of the critical region is also examined and confronted with freeze-out states in these experiments.
Categories: hep-ph