The NNLO quark beam function for jet-veto resummation

TL;DR

This paper computes the quark beam function at NNLO for jet-veto resummation, enabling more precise theoretical predictions for processes with jet vetoes in high-energy physics.

Contribution

It introduces a novel automated framework for calculating beam functions in Mellin space and extends jet-veto resummation accuracy to NNLL$'$ for quark-initiated processes.

Findings

Computed the quark beam function at NNLO using the collinear-anomaly framework.

Automated the calculation of beam functions in Mellin space.

Provided ingredients for extending jet-veto resummation to NNLL$'$ accuracy.

Abstract

We consider the quark beam function that describes collinear initial-state radiation that is constrained by a veto on reconstructed jets. As the veto is imposed on the transverse momenta of the jets, the beam function is subject to rapidity divergences, and we use the collinear-anomaly framework to extract the perturbative matching kernels to next-to-next-to-leading order (NNLO) in the strong-coupling expansion. Our calculation is based on a novel framework that automates the computation of beam functions in Mellin space and it provides the ingredients to extend jet-veto resummations for quark-initiated processes to NNLL$'$ accuracy.