Recent results on Bose-Einstein correlations by the PHENIX Experiment

Abstract

We present the measurement of charged pion two-particle correlation functions in $\sqrt{s_{NN}}=$ 39, 62 and 200 GeV Au+Au collisions. The measured correlation functions for all collision energies, centralities and average transverse masses can be statistically well described by Bose-Einstein correlation functions from Levy-shaped source distributions. We extract the correlation strength parameter $\lambda$, Levy index $\alpha$ and Levy scale parameter $R$ as functions of average pair transverse mass. We observe that the Levy index $\alpha$ differs from the Gaussian case of $\alpha=2$ and also from the conjectured value at the critical point. The correlation strength $\lambda$ shows a decrease for small transverse masses, which may be in conjunction with an increased number of decay pions in the given kinematic domain. The Levy scale $R$ shows a hydrodynamic type of scaling behavior. Furthermore, the appearance of a new scaling variable $\widehat{R}$ is observed.