Eccentricity fluctuation effects on elliptic flow in relativistic heavy ion collisions

TL;DR

This paper investigates how initial eccentricity fluctuations influence the elliptic flow coefficient v_2 in relativistic heavy-ion collisions, using a hybrid model with different initial condition models to assess their impact.

Contribution

It demonstrates the effect of eccentricity fluctuations on v_2 in Au+Au and Cu+Cu collisions, highlighting their significance especially in smaller systems like Cu+Cu.

Findings

Eccentricity fluctuations modestly affect v_2 in semicentral Au+Au collisions.

Eccentricity fluctuations significantly enhance v_2 in Cu+Cu collisions.

Different initial condition models show varying impacts on eccentricity fluctuations.

Abstract

We study effects of eccentricity fluctuations on the elliptic flow coefficient v_2 at mid-rapidity in both Au+Au and Cu+Cu collisions at sqrt{s_NN}=200 GeV by using a hybrid model that combines ideal hydrodynamics for space-time evolution of the quark gluon plasma phase and a hadronic transport model for the hadronic matter. For initial conditions in hydrodynamic simulations, both the Glauber model and the color glass condensate model are employed to demonstrate the effect of initial eccentricity fluctuations originating from the nucleon position inside a colliding nucleus. The effect of eccentricity fluctuations is modest in semicentral Au+Au collisions, but significantly enhances v_2 in Cu+Cu collisions.