The Effect of a Rapidity Gap Veto on the Discrete BFKL Pomeron

TL;DR

This paper studies how imposing a rapidity gap veto affects the discrete BFKL Pomeron spectrum, showing it reduces energy growth and suppresses small transverse momentum regions, especially impacting the lowest eigenfunctions.

Contribution

It introduces an analysis of the sensitivity of the discrete BFKL spectrum to rapidity vetoes, highlighting the spectral changes and energy growth suppression.

Findings

Eigenvalues decrease with larger rapidity veto

Growth with energy is reduced by the veto

Suppression occurs in small transverse momentum regions

Abstract

We investigate the sensitivity of the discrete BFKL spectrum, which appears in the gluon Green function when the running coupling is considered, to a lower cut-off in the relative rapidities of the emitted particles. We find that the eigenvalues associated to each of the discrete eigenfunctions decrease with the size of the rapidity veto. The effect is stronger on the lowest eigenfunctions. The net result is a reduction of the growth with energy for the Green function together with a suppression in the regions with small transverse momentum.