Color-glass condensate beyond the Gaussian approximation

TL;DR

This paper extends the Gaussian model in the color-glass condensate framework to a more general form, allowing for non-Gaussian distributions and providing a basis for improved numerical and phenomenological studies of nuclear structure at high energies.

Contribution

It introduces a generalized, non-Gaussian model for the color density in the CGC framework, enabling more flexible and accurate calculations of Wilson-line correlators.

Findings

Small-dipole behavior shifts from quadratic to a power law

Model accommodates stable probability distributions for color density

Facilitates numerical and phenomenological applications in high-energy QCD

Abstract

In the high-energy limit, perturbative calculations in QCD are conveniently done using the dipole picture which factorizes the scattering amplitude into a perturbative part and the nonperturbative scattering off the nuclear target, described using correlators of Wilson lines. These correlators can be computed in the color-glass condensate effective field theory by using a Gaussian model for the color density of the target. In this work, we generalize the Gaussian model to a generic function that is local in the transverse coordinates and the light-cone time, and show how to compute physical Wilson-line correlators in this model. We also consider a simple model for the color density based on stable probability distributions and show that the small-dipole behavior of the dipole amplitude is modified from quadratic to a power law, where the power is given by the stability parameter of the distribution. This generalization of the Gaussian model is suitable for numerical applications in the high-energy limit and can be used in future phenomenological studies of the nuclear structure.