New observables to test the Color Glass Condensate beyond the large-N_c limit

TL;DR

This paper explores new observables in high-energy QCD to test the Color Glass Condensate beyond the large-N_c approximation, using the JIMWLK framework and Gaussian truncation for practical calculations.

Contribution

It introduces meson production cross-sections as new observables sensitive to effects beyond the large-N_c limit and higher twist, with a practical method for their evolution.

Findings

Meson production cross-sections can probe beyond large-N_c effects.

Four point functions' evolution derived from JIMWLK framework.

Gaussian truncation enables efficient calculations beyond large-N_c.

Abstract

The JIMWLK framework offers a powerful tool to calculate the energy dependence of QCD observables at high energies. Despite a growing number of observables considered for phenomenological analysis, few features of JIMWLK evolution beyond its evolution speed are yet well constrained by experiment. We argue that meson production cross-sections have the potential to provide qualitatively new insights and allow to address issues both beyond the large-N_c limit and at higher twist. These cross-sections generically contain four point functions whose evolution is shown to follow from the JIMWLK framework. The Gaussian truncation is used to provide an efficient and practical means of calculating the evolution of four point correlators beyond the large-N_c limit.