Fine structures of azimuthal correlations of two gluons in the glasma

TL;DR

This paper studies the detailed azimuthal correlations of gluons in the glasma produced in high-energy proton-proton collisions, revealing fine structures linked to saturation effects at specific transverse momenta.

Contribution

It uncovers fine structures in azimuthal correlations of gluons in the glasma, associated with saturation momentum, using the CGC formalism in p-p collisions at 7 TeV.

Findings

Azimuthal correlations show peaks at 0 and π radians.

Fine structures such as bumps or shoulders are observed between the peaks.

These structures are related to saturation momentum and appear around 1.8 GeV/c.

Abstract

We investigate the azimuthal correlations of the glasma in p-p collisions at $\sqrt{s_{\mathrm{NN}}}=7$ TeV by using the CGC formalism. As expected, the azimuthal correlations show two peaks at $\Delta\phi=0$ and $\pi$ which represent collimation production in CGC. Beyond that, azimuthal correlations show fine structures, i.e. bumps or shoulders between the two peaks, when at least one gluon has small $x$. The structures are demonstrated to be associated with saturation momentum, and likely appear at transverse momentum around $2Q_{\mathrm{sp}}=1.8$ GeV$/$c.