Evolution of collectivity as a signal of quark gluon plasma formation in heavy ion collisions

TL;DR

This paper proposes using dilepton interferometry in heavy-ion collisions to detect quark-gluon plasma formation by analyzing the mass dependence of HBT radii, revealing the evolution of collective flow and phase durations.

Contribution

It introduces a novel method to identify quark-gluon plasma formation through dilepton interferometry and the analysis of HBT radii variations with invariant mass.

Findings

Non-monotonic variation of HBT radii indicates QGP formation

Mass dependence of radii reveals collective flow development

Ratio R_out/R_side estimates phase lifetimes

Abstract

A measurement for studying the mass dependence of the dilepton interferometry in relativistic heavy-ion collision experiments as a tool to characterize the quark-gluon phase is proposed. In calculations involving dileptons, we show that the mass dependence of radii extracted from the virtual photon (dilepton) interferometry provide access to the development of collective flow with time. It is argued that the non-monotonic variation of HBT radii with invariant mass of the lepton pairs signals the formation of quark gluon plasma in heavy ion collisions. Our proposal of experimentally measuring the ratio, $R_{\mathrm out}/R_{\mathrm side}$ for dileptons can be used to estimate the average life times of the partonic as well as the hadronic phases.