Finite Numbers of Sources, Particle Correlations and the Color Glass Condensate

TL;DR

This paper demonstrates that the Color Glass Condensate model predicts significant elliptic flow in small collision systems, matching experimental observations, due to quantum interference and source fluctuations.

Contribution

It introduces a finite-source approach within the Color Glass Condensate framework to explain azimuthal anisotropy in small collision systems, aligning with LHC data.

Findings

Color Glass Condensate produces substantial elliptic flow for finite sources.

Flow characteristics match semi-quantitative features observed in experiments.

Flow arises from quantum interference and source position fluctuations.

Abstract

We show that for a finite number of emitting sources, the Color Glass Condensate produces substantial elliptic azimuthal anisotropy, characterized by $v_2$, for two and four particle correlations for momentum greater than or of the order the saturation momentum. The flow produced has the correct semi-quantitative features to describe flow seen in LHC experiments with p-Pb and pp collisions. This flow is induced by quantum mechanical interference between the waves of produced particles, and the flow itself is coupled to fluctuations in the positions of emitting sources. We shortly discuss generalizing these results to odd $v_n$, to correlations involving larger number of particles, and to transverse momentum scales $\Lambda_{\rm QCD} \ll p_T \ll Q_{\rm sat}$.