Two-pion interferometry for the granular sources in ultrarelativistic heavy ion collisions

TL;DR

This paper models two-pion interferometry in ultrarelativistic heavy ion collisions using a granular quark-gluon plasma droplet source, successfully matching experimental data and revealing effects of system breakup time and droplet expansion on HBT radii.

Contribution

It introduces a granular source model for pion interferometry that accurately reproduces experimental HBT measurements in heavy ion collisions.

Findings

The model agrees with experimental pion spectra and HBT radii.

Larger initial breakup time increases HBT radii.

Droplet expansion results in small R_out/R_side ratios.

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 $\sqrt{s_{NN}}=200$ GeV Au-Au and $\sqrt{s_{NN}}=2.76$ TeV Pb-Pb most central collisions. In the granular source model the larger initial system breakup time 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 small ratios of the transverse HBT radii $R_{\rm out}/R_{\rm side}$.