Unruh thermalization, gluon condensation, and freeze-out

The deconfinement transition and the hadronization mechanism at high energy are related to the quark-antiquark string breaking, and the corresponding temperature depends on the string tension sigma. In the Unruh scheme of hadron production, it turns out T = root sigma/2 pi, with sigma similar or equal to epsilon(vac), the vacuum energy density. In heavy ion collisions at lower energy, i.e., large baryonchemical potential, mu(B), the dynamics is dominated by Fermi statistics and baryon repulsion. However, one can still consider epsilon(vac) as the relevant physical scale, and its evaluation as a function of the baryon density, in a nuclear matter approach, gives dynamical information on the mu(B) dependence of the hadronization temperature and on the value of the critical end point in the T - mu(B) plane.