Survival rate of initial azimuthal anisotropy in a multi-phase transport model

TL;DR

This study examines how initial azimuthal momentum anisotropy persists through the evolution of Au+Au collisions at 200 GeV using the AMPT model, revealing its dependence on transverse momentum, collision centrality, and energy.

Contribution

It introduces the concept of the survival rate of initial momentum anisotropy and analyzes its dependence on various collision parameters within the AMPT model.

Findings

Survival rate increases with transverse momentum, reaching ~100% at 2.5 GeV/c.

Survival rate decreases with collision centrality and energy.

Initial anisotropy with a random reference does not survive in the participant plane v2 but does in two-particle cumulant v2.

Abstract

We investigate the survival rate of an initial momentum anisotropy (${v}_2^{ini}$), not spatial anisotropy, to the final state in a multi-phase transport (AMPT) model in Au+Au collisions at $\sqrt{s_{NN}}$=200~GeV. It is found that both the final-state parton and charged hadron $v_2$ show a linear dependence versus $v_2^{ini}\{\rm PP\}$ with respect to the participant plane (PP). It is found that the slope of this linear dependence (referred to as the survive rate) increases with transverse momentum ($p_T$), reaching~$\sim$100\% at $p_T$$\sim$2.5 GeV/c for both parton and charged hadron. The survival rate decreases with collision centrality and energy, indicating decreasing survival rate with increasing interactions. It is further found that a $v_2^{ini}\{\rm Rnd\}$ with respect to a random direction does not survive in $v_2\{\rm PP\}$ but in the two-particle cumulant $v_2\{2\}$. The dependence of $v_2\{2\}$ on $v_2^{ini}\{\rm Rnd\}$ is quadratic rather than linear.