Rapidity veto effects in the NLO BFKL equation

TL;DR

This paper investigates how suppressing gluon emissions close in rapidity affects the NLO BFKL equation, finding that removing collinear logarithms diminishes the veto's impact, thus supporting the validity of multi-Regge kinematics.

Contribution

It demonstrates that the rapidity veto effect is significantly reduced after removing unphysical collinear logarithms, validating the use of multi-Regge kinematics in NLO BFKL calculations.

Findings

Rapidity veto effect is reduced after collinear logarithm removal.

Supports the use of multi-Regge kinematics in NLO BFKL.

Collinear logarithms are unphysical and should be removed.

Abstract

We examine the effect of suppressing the emission of gluons which are close by in rapidity in the BFKL framework. We show that, after removing the unphysical collinear logarithms which typically arise in formally higher orders of the perturbative expansion, the effect of the rapidity veto is greatly reduced. This is an important result, since it supports the use of multi-Regge and quasi-multi-Regge kinematics which are implemented in the leading and next-to-leading order BFKL formalism.