On the Dihadron Angular Correlations in Forward $pA$ collisions

TL;DR

This paper investigates dihadron angular correlations in forward proton-nucleus collisions, incorporating parton shower effects into the saturation framework, and compares results with experimental data to identify saturation signals.

Contribution

It introduces the first detailed numerical study combining parton shower effects with the saturation formalism in dihadron correlations.

Findings

Good agreement with RHIC $pp$ and $dAu$ data

Establishes a baseline for $pp$ collisions with minimal saturation effects

Provides predictions for $pAu$ collisions to detect saturation signals

Abstract

Dihadron angular correlations in forward $pA$ collisions have been considered as one of the most sensitive observables to the gluon saturation effects. In general, both parton shower effects and saturation effects are responsible for the back-to-back dihadron angular de-correlations. With the recent progress in the saturation formalism, we can incorporate the parton shower effect by adding the corresponding Sudakov factor in the saturation framework. In this paper, we carry out the first detailed numerical study in this regard, and find a very good agreement with previous RHIC $pp$ and $dAu$ data. This study can help us to establish a baseline in $pp$ collisions which contains little saturation effects, and further make predictions for dihadron angular correlations in $pAu$ collisions, which will allow to search for the signal of parton saturation.