Next-to-leading order predictions for Z gamma+jet and Z gamma gamma final states at the LHC

TL;DR

This paper provides next-to-leading order theoretical predictions for Z gamma+jet and Z gamma gamma final states at the LHC, including photon radiation effects and fragmentation, with uncertainty estimates and implementation in MCFM.

Contribution

It introduces NLO calculations for Z gamma+jet and Z gamma gamma processes, incorporating photon radiation, fragmentation, and a reliable scale uncertainty estimation, implemented in a public code.

Findings

Predictions include photon radiation effects from leptons.

Fragmentation contributions are accounted for.

Scale uncertainties are reliably estimated.

Abstract

We present next-to-leading order predictions for final states containing leptons produced through the decay of a Z boson in association with either a photon and a jet, or a pair of photons. The effect of photon radiation from the final state leptons is included and we also allow for contributions arising from fragmentation processes. Phenomenological studies are presented for the LHC in the case of final states containing charged leptons and in the case of neutrinos. We also use the procedure introduced by Stewart and Tackmann to provide a reliable estimate of the scale uncertainty inherent in our theoretical calculations of jet-binned Z gamma cross sections. These computations have been implemented in the public code MCFM.