Energy Loss in Hadron Production in pp and Heavy Ion Collisions

The experimental data on inclusive hadron spectra measured in proton-proton and heavy ion collisions at SPS, RHIC and LHC are analyzed in the framework of the z-scaling. The dependence of the energy loss on the transverse momentum, collision energy and centrality is studied. Two scenarios of hadron production (with small and large specific heat) in nuclear reactions at RHIC and SPS energies are tested. Search for signatures of the phase transition of the nuclear matter and the Critical Point in heavy ion collisions is discussed.