Asymptotics and preasymptotics at small x

TL;DR

This paper examines the effects of running-coupling and higher-order corrections on the small-x gluon-gluon splitting function, highlighting differences between asymptotic and preasymptotic behaviors relevant for phenomenology.

Contribution

It provides an analysis of the impact of running-coupling corrections on small-x splitting functions and discusses their phenomenological relevance compared to asymptotic predictions.

Findings

Asymptotic small-x behavior has limited relevance to phenomenology.

Higher-order corrections significantly influence the splitting function.

Similarities with the Balitsky-Kovchegov equation due to infrared cutoff.

Abstract

This talk discusses the relative impact of running-coupling and other higher-order corrections on the small-x gluon-gluon splitting function. Comments are made on similarities with some aspects of the Balitsky-Kovchegov equation, which arise because of the presence of an effective infrared cutoff in both cases. It is emphasised that, at least in the splitting-function case, the asymptotic small-x behaviour has little relevance to the phenomenologically interesting preasymptotic region. This is illustrated with the aid of a convolution of the resummed splitting function with a toy gluon distribution.