Abstract
In high-energy heavy ion collisions a hot and dense medium is formed, where the or chiral symmetry may temporarily be restored. As a consequence, the mass of the (958) mesons may be reduced to its quark model value, and the abundance of mesons at low may be enhanced by more than a factor of 10. The intercept parameter of the charged pion Bose Einstein correlations provides a sensitive observable of the possibly enhanced abundance. We have analyzed data from central AuAu reactions measured at the BNL Relativistic Heavy Ion Collider (RHIC), using extensive Monte Carlo simulations based on six popular models for hadronic multiplicities. Based on the combined STAR and PHENIX data set, and on various systematic investigations of resonance multiplicities and model parameters, we conclude that in central AuAu reactions the mass of the meson is reduced by , at the 99.9% confidence level in the considered model class. Such a significant mass modification may indicate the restoration of the symmetry in a hot and dense hadronic matter and the return of the ninth “prodigal” Goldstone boson. A similar analysis of NA44 SPb data at top CERN Super Proton Synchroton (SPS) energies showed no significant in-medium mass modification.
7 More- Received 22 October 2010
DOI:https://doi.org/10.1103/PhysRevC.83.054903
©2011 American Physical Society