Two-loop mixed QCD-electroweak amplitudes for $Z+$jet production at the LHC: bosonic corrections

TL;DR

This paper calculates the bosonic part of two-loop mixed QCD-electroweak amplitudes for Z+jet production at the LHC, enhancing the precision of background modeling for new physics searches.

Contribution

It introduces a novel method for calculating two-loop amplitudes in the 't Hooft-Veltman scheme and provides numerical results crucial for collider phenomenology.

Findings

Numerical two-loop amplitudes for Z+jet production are obtained.

The method reduces computational complexity and improves accuracy.

Results support better background estimates for monojet searches.

Abstract

We present a calculation of the bosonic contribution to the two-loop mixed QCD-electroweak scattering amplitudes for $Z$-boson production in association with one hard jet at hadron colliders. We employ a method to calculate amplitudes in the 't Hooft-Veltman scheme that reduces the amount of spurious non-physical information needed at intermediate stages of the computation, to keep the complexity of the calculation under control. We compute all the relevant Feynman integrals numerically using the Auxiliary Mass Flow method. We evaluate the two-loop scattering amplitudes on a two-dimensional grid in the rapidity and transverse momentum of the $Z$ boson, which has been designed to yield a reliable numerical sampling of the boosted-$Z$ region. This result provides an important building block for improving the theoretical modelling of a key background for monojet searches at the LHC.