Exploring the QCD phase diagram via the collision energy dependence of multi-particle femtoscopy with PHENIX

Máté Csanád

doi:10.1088/1742-6596/1602/1/012009

Abstract

Exploration of the rich structure of the QCD phase diagram is an important topic in the RHIC heavy ion program. One of the ultimate goals of this program is to search for the critical endpoint. Investigation of the space-time structure of hadron emissions at various phase transition points using Bose-Einstein correlations of identical bosons may provide insight on the location of the critical endpoint. PHENIX has performed comprehensive measurements of the Bose-Einstein correlation in Au+Au collisions at , 19, 27, 39, 62.4, and 200 GeV, where we incorporated Lévy-type source functions to describe the measured correlation functions. We put particular focus on one of the parameters of the Lévy-type source functions, the index of stability α, which is related to one of the critical exponents (the so-called correlation exponent ɳ). We have measured its collision energy and centrality dependence. We have also extended our analysis from two-particle to three-particle correlations to characterize the nature of the hadron emission source. The three particle correlations confirmed the findings of the two-particle correlations, and also provide insight on the pion production mechanism beyond the core-halo model.

Highlights

Femtoscopy is an important subfield of high energy nuclear and particle physics, as it allows us to investigate the space-time structure of femtometer scale processes
The most important equation utilized in two-particle femtoscopic correlations is one that relates the pair source D2(r, K) and the correlation function C2(q, K): C2(q, K)
For expanding sources the obtained radius will be related to the homogeneity length of the source for particles of given momenta [3]. It was observed [3,4,5,6,7] that when investigating two-particle correlation functions, one has to go beyond the Gaussian approximation

Summary

Introduction

Femtoscopy (coined by Ledniczky [1]) is an important subfield of high energy nuclear and particle physics, as it allows us to investigate the space-time structure of femtometer scale processes. The C2 correlation function can be written up with the single particle source S(r, p) (D2(r, K) is the autoconvolution of S(r, p) in the first variable with p = K): S(q, K)

Results

Conclusion