Phi-measure of pions in high energy heavy-ion collisions

Abstract

Event-by-Event fluctuations for high energy heavy-ion collisions are investigated. The $Φ$-measures are calculated for pions. It is found that multiparticle symmetrization correlation has great influence on the value of $Φ$ if the phase space density is high. Previous derivation of $Φ$-measure has neglected multiparticle quantum correlation. So the explanation of $Φ$-measure as a measure of dynamical correlation is reasonable only when multiparticles quantum correlation effects are smaller. We argue that the $Φ$-measure might be applicable at the SPS energy where the pion phase space density is much less than one.