Two-pion interferometry for the granular sources in the heavy ion collisions at RHIC and LHC energies

TL;DR

This paper models two-pion interferometry in ultrarelativistic heavy ion collisions using a granular source of quark-gluon plasma droplets, successfully matching experimental data and explaining HBT radii differences between RHIC and LHC energies.

Contribution

It introduces a granular source model for quark-gluon plasma droplets that reproduces experimental pion spectra and HBT radii in heavy ion collisions at RHIC and LHC energies.

Findings

The model agrees well with experimental data.

Larger initial system breakup time at LHC leads to bigger HBT radii.

The ratio R_out/R_side remains close to 1 due to droplet expansion and emission timing.

Abstract

We investigate the two-pion interferometry in ultrarelativistic heavy ion collisions in the granular source model of quark-gluon plasma droplets. The pion transverse momentum spectra and HBT radii of the granular sources agree well with the experimental data of the most central Au-Au collisions at $\sqrt{s_{NN}}=200$ GeV at RHIC and Pb-Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV at LHC. In the granular source model the larger initial system breakup time for the LHC collisions as compared to the RHIC collisions may lead to the larger HBT radii $R_{\rm out}$, $R_{\rm side}$, and $R_{\rm long}$. However, the large droplet transverse expansion and limited average relative emitting time of particles in the granular source lead to the ratio of the transverse HBT radii $R_{\rm out}/R_{\rm side} \sim 1$.