Effect of space-momentum correlations on the constituent quark number scaling of hadron elliptic flows

TL;DR

This paper investigates how space-momentum correlations in quark distributions affect the scaling of hadron elliptic flows, revealing conditions under which quark number scaling holds or breaks in heavy ion collisions.

Contribution

It demonstrates that quark number scaling of hadron elliptic flow can persist despite local anisotropies, but is sensitive to radial flow anisotropy and quark momentum dispersion.

Findings

Quark number scaling can hold despite large local anisotropic flow.

Radial flow anisotropy and quark momentum dispersion break the scaling.

Scaling is robust under certain conditions despite complex quark distributions.

Abstract

Using models ranging from schematic one with a simple quark distribution to more realistic blast wave, we study the elliptic flow of hadrons produced from coalescence of quarks and antiquarks in the quark-gluon plasma that is formed in ultrarelativistic heavy ion collisions. In particular, we study effects due to azimuthal anisotropy in the local transverse momentum distribution of quarks, as generated by their position-momentum correlations as a result of radial flow and/or jet quenching. We find that even if quarks have large local non-elliptic anisotropic flow, the elliptic flow of produced hadrons can still scale with their constituent quark numbers. This scaling is, however, broken if the radial flow of coalescing quarks is anisotropic and/or if the momentum dispersion of quarks inside hadrons is included.