Lévy HBT Results at NA61/SHINE

Barnabás Pórfy

doi:10.3390/universe5060154

Abstract

Bose–Einstein (or Hanbury–Brown and Twiss (HBT)) momentum correlations reveal the space–time structure of the particle emitting source created in high energy nucleus–nucleus collisions. In this paper we present the latest NA61/SHINE measurements of Bose–Einstein correlations of identified pion pairs and their description based on Lévy distributed sources in Be + Be collisions at 150A GeV/c. We investigate the transverse mass dependence of the Lévy source parameters and discuss their possible interpretations.

Highlights

NA61/SHINE is a fixed target experiment at the CERN Super Proton Synchrotron (SPS)
The rapidity region of analyzed particles is 0.85 < η < 4.85, the azimuthal coverage is 2π; n this track sample, we identified pions based on their deposited energy dE/dx in the time projection chambers (TPC) gas and charge obtained from the curvature of their trajectories in the magnetic field
Using the results from the free parameter fit, we fitted a constant function to the α values for all m T bins, as well as the formula of Equation (11) to the R values in each bin

Summary

Introduction

NA61/SHINE is a fixed target experiment at the CERN Super Proton Synchrotron (SPS). One of its main aims is to study the phase diagram of QCD. Due to critical fluctuations and the appearance of large scale spatial correlations, similar power-law tailed sources may be present [7]. The halo consists of pions created from longer lived (compared to the usual source size of a few femtometers) resonances and general background In this picture, the λ parameter turns out to be connected to the ratio of the Core and the Halo as follows: λ=. Critical exponents are universal in the sense that they take the same values in case of physical systems belonging to the same universality class It has been shown [11] that the universality class of QCD is that of the 3D Ising model. The phase diagram with different energies and systems and measure the values of the α exponent, we might be able to gain more information on the location and characteristics of the CEP

Measurement Details

Results

Conclusions