Indirect Observation of an In-Medium ${\ensuremath{\eta}}^{\ensuremath{'}}$ Mass Reduction in $\sqrt{{s}_{NN}}=200\text{ }\text{ }\mathrm{GeV}$ $\mathrm{Au}+\mathrm{Au}$ Collisions

Indirect Observation of an In-Medium $η^{'}$ Mass Reduction in $\sqrt{s_{N N}} = 200 GeV$ $Au + Au$ Collisions

T. Csörgő, R. Vértesi, and J. Sziklai

Phys. Rev. Lett. 105, 182301 – Published 25 October 2010

Abstract

PHENIX Collaboration and STAR Collaboration data on the intercept parameter of the two-pion Bose-Einstein correlation functions in $\sqrt{s_{N N}} = 200 GeV$ $Au + Au$ collisions are analyzed in terms of different models of hadronic multiplicities. To describe this combined PHENIX and STAR data set, an in-medium $η^{'}$ mass reduction of at least 200 MeV is needed, at the 99.9% confidence level in the considered model class. Such a significant $η^{'}$ mass modification may indicate the restoration of the $U_{A} (1)$ symmetry in a hot and dense hadronic matter and the return of the 9th “prodigal” Goldstone boson.

Received 31 December 2009

DOI:https://doi.org/10.1103/PhysRevLett.105.182301

Authors & Affiliations

T. Csörgő

Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, USA and MTA KFKI RMKI, H–1525 Budapest 114, P.O. Box 49, Hungary

R. Vértesi and J. Sziklai