Higher Flow Harmonics in Heavy Ion Collisions from STAR

TL;DR

This paper presents measurements of higher flow harmonics in heavy ion collisions from STAR, analyzing their dependence on centrality, transverse momentum, and pseudorapidity, and comparing results with theoretical models.

Contribution

It provides new detailed measurements of flow harmonics up to the sixth order and their correlations, enhancing understanding of initial conditions and expansion dynamics in heavy ion collisions.

Findings

Higher harmonics decrease rapidly for central collisions.

Trends align with models including hot-spots in initial energy density.

Flow coefficients depend on centrality, pT, and ta, consistent with theoretical expectations.

Abstract

We report STAR measurements relating to higher flow harmonics including the centrality dependence of two- and four-particle cumulants for harmonics 1 to 6. Two-particle correlation functions vs. \Delta\eta and \Delta\phi are presented for pT and number correlations. We find the power spectra (Fourier Transforms of the correlation functions) for central collisions drop quickly for higher harmonics. The \Delta\eta dependence of v3{2}2 and the pT and centrality dependence of v2 and v3 are studied. Trends are conistent with expectations from models including hot-spots in the initial energy density and an expansion phase. We also present v3 and v2{2}2 - v2{4}2 vs. \surdsNN .