Emission of light mesons directly from the surface of quark-gluon plasma

Abstract

On the basis of hydrodynamic model of evolution we consider emission of lightest (\pi,K,\eta,\rho,\omega,K^*) mesons directly from the surface of quark-gluon plasma, created in the heavy ion collision, with accounting of their absorption by surrounding hadronic gas. We evaluate upper and lower limits on yields of these direct mesons in Pb+Pb collisions at SpS, RHIC and LHC energies, and find, that even in the case of the lowest yield, direct K, \eta and heavier mesons dominate over freeze-out ones at soft p_t (p_t < 0.5 GeV/c). This leads to enhancement of the low p_t production of these mesons which hardly can be explained within pure hadronic gas scenario, and can be considered as quark-gluon plasma signature.