Comparison of the Color Glass Condensate to di-hadron correlations in proton-proton and proton-nucleus collisions

TL;DR

This paper compares the Color Glass Condensate theory to di-hadron correlation data from high-energy proton-proton and proton-lead collisions, providing evidence for gluon saturation effects and quantum interference in the initial state.

Contribution

It offers a detailed comparison between CGC predictions and experimental data, highlighting the role of gluon distributions and quantum effects in particle correlations.

Findings

Good agreement between CGC and LHC data on di-hadron correlations

Sensitivity of azimuthal collimation to gluon distribution shapes

Estimates for di-hadron yields in deuteron-gold collisions at RHIC

Abstract

We perform a detailed comparison of long range rapidity correlations in the Color Glass Condensate framework to high multiplicity di-hadron data in proton-proton and proton-lead collisions from the CMS, ALICE and ATLAS experiments at the LHC. The overall good agreement thus far of the non-trivial systematics of theory with data is strongly suggestive of gluon saturation and the presence of subtle quantum interference effects between rapidity separated gluons. In particular, the yield of pairs collimated in their relative azimuthal angle $\Delta\phi\sim 0$, is sensitive to the shape of unintegrated gluon distributions in the hadrons that are renormalization group evolved in rapidity from the beam rapidities to those of the measured hadrons. We present estimates for the collimated di-hadron yield expected in central deuteron-gold collisions at RHIC.