PION THERMALISATION IN RELATIVISTIC HEAVY ION COLLISIONS

摘要

We consider a model of thermalisation of pions due to elastic scattering and define the region of applicability of this model. In this region the chemical potential is positive. We analyse the absorptive and dispersive properties of pions during thermalisation, by calculating the pion collective potential. The pion gas can be thermally equilibrated but it will be out of chemical equilibrium. We define the degree of thermalisation near freeze-out at the level similar to 70% for S + S and similar to 90% for O + Au collisions at CERN. We find that the effect of the chemical potential in pion spectra is stronger than the temperature effect at p perpendicular to less than or equal to 200 MeV. [References: 27]