CGC/saturation approach for high energy soft interactions: $\mathbf{v_2}$ in proton-proton collisions

TL;DR

This paper develops a CGC/saturation-based model for high energy soft interactions, showing it can explain a significant portion of the observed azimuthal correlations in proton-proton collisions without invoking quark-gluon plasma formation.

Contribution

It introduces a model that accounts for azimuthal correlations in proton-proton collisions using the CGC/saturation framework, emphasizing the density variation mechanism.

Findings

The model predicts $v_2$ values about 60-70% of experimental measurements.

Azimuthal correlations are primarily attributed to CGC/saturation physics.

Other mechanisms like Bose enhancement and local anisotropy are also considered.

Abstract

In this paper we continue our program to construct a model for high energy soft interactions, based on the CGC/saturation approach. We demonstrate that in our model which describes diffractive physics as well as multi-particle production at high energy, the density variation mechanism leads to the value of $v_2$ which is about $60\% \div 70\%$ of the measured $v_2$. Bearing in mind that in CGC/saturation approach there are two other mechanisms present: Bose enhancement in the wave function and local anisotropy, we believe that the azimuthal long range rapidity correlations in proton-proton collisions stem from the CGC/saturation physics, and not from quark-gluon plasma production.