Azimuthal angle and rapidity dependence of di-hadron correlations in QCD

TL;DR

This paper explores recent QCD phenomena observed in various collision types, emphasizing di-hadron correlation measurements to identify novel effects from small-x gluon dynamics, including azimuthal and rapidity dependencies.

Contribution

It highlights the importance of di-hadron correlations in revealing non-linear small-x gluon effects across different collision systems.

Findings

Observation of azimuthal angle dependence in di-hadron correlations.

Detection of long-range rapidity correlations in high-multiplicity collisions.

Evidence supporting non-linear gluon dynamics at small-x.

Abstract

I discuss novel QCD phenomena recently observed in p+p, p+A and A+A collisions, that result from the non-linear dynamics of small-x gluons. I focus on di-hadron correlation measurements, as opposed to single-hadron observables often too inclusive to distinguish possible new effects from established mechanisms. Specifically, I discuss angular correlations of forward di-hadrons in d+Au collisions and long-range rapidity correlations in high-multiplicity p+p and Au+Au collisions.