Enhanced event-by-event fluctuations in pion multiplicity as a signal of disoriented chiral condensates in relativistic heavy-ion collisions

Abstract

The factorial moments of the pion multiplicity distributions are calculated with HIJING and UrQMD and found to be independent of the ${p}_{T}$ range included, in contrast to recent simulations with the linear $\ensuremath{\sigma}$ model which leads to large enhancements for pions with transverse kinetic energies below 200 MeV. This supports the use of the ratio of the factorial moments of low and high ${p}_{T}$ pions as a signal of ``new'' physics at low momentum scales, such as the formation of disoriented chiral condensates.