Running Coupling Effects in Small-x QCD

TL;DR

This paper investigates how the running of the coupling constant influences small-x QCD phenomena, including gluon saturation, the energy dependence of saturation momentum, and geometrical scaling, highlighting the dominance of running coupling effects.

Contribution

It derives the next-to-leading order nonlinear evolution equation for small-x QCD and analyzes the impact of running coupling effects on saturation and scaling behaviors.

Findings

Running coupling effects dominate over Pomeron loop contributions.

The saturation momentum's energy dependence is significantly affected by the running coupling.

Geometrical scaling emerges prominently due to running coupling effects.

Abstract

We study effects of the running of the coupling in QCD at small Bjorken-x and in particular the ones related to gluon saturation. After introducing the steps taken to the derivation of the next to leading order nonlinear evolution equation, we discuss the infrared sensitivity of the Pomeron intercept, the energy dependence of the saturation momentum and the appearance of geometrical scaling, and the dominance of the running coupling effects over the ones introduced by loops of Pomerons.