Analysis of pion elliptic flow and Hanbury-Brown–Twiss interferometry in a granular quark-gluon plasma droplet model

Abstract

In many simulations of high-energy heavy-ion collisions on an event-by-event analysis, it is known that the initial energy density distribution in the transverse plane is highly fluctuating. Subsequent longitudinal expansion will lead to many longitudinal tubes of quark-gluon plasma that have tendencies to break up into many spherical droplets because of sausage instabilities. We are therefore motivated to use a model of quark-gluon plasma granular droplets that evolve hydrodynamically to investigate pion elliptic flows and Hanbury-Brown--Twiss (HBT) interferometry. We find that the data of pion transverse momentum spectra, elliptic flows, and HBT radii in $\sqrt{{s}_{\mathit{NN}}}=200$ GeV Au+Au collisions at the BNL Relativistic Heavy Ion Collider can be described well by an expanding source of granular droplets with an anisotropic velocity distribution.