W±Z production at hadron colliders in NNLO QCD

Massimiliano Grazzini,Marius Wiesemann,Dirk Rathlev,Stefan Kallweit

doi:10.1016/j.physletb.2016.08.017

Abstract

We report on the first computation of the next-to-next-to-leading order (NNLO) QCD corrections to $W^{\pm}Z$ production in proton collisions. We consider both the inclusive production of on-shell $W^{\pm}Z$ pairs at LHC energies and the total $W^{\pm}Z$ rates including off-shell effects of the $W$ and $Z$ bosons. In the off-shell computation, the invariant mass of the lepton pairs from the $Z$ boson decay is required to be in a given mass window, and the results are compared with the corresponding measurements obtained by the ATLAS and CMS collaborations. The NNLO corrections range from 8% at $\sqrt{s}$=7 TeV to 11% at $\sqrt{s}$=14 TeV and significantly improve the agreement with the LHC data at $\sqrt{s}$=7 and 8 TeV.

Highlights

We report on the first computation of the next-to-next-to-leading order (NNLO) QCD corrections to W ±Z production in proton collisions
While the W +W − and ZZ cross sections can be computed at NNLO in the on-shell approximation using two-loop amplitudes for two massive vector bosons of the same mass, as done in Ref. [16] and Ref. [17], respectively, the W ±Z production process requires the amplitudes with different masses of the vector-boson pairs already in the on-shell approximation
The required two-loop amplitudes were presented in Refs. [18, 19] in the form of helicity amplitudes for all vector-boson pair production processes, enabling at the same time the computation of NNLO corrections to W ±Z production as well as the inclusion of off-shell effects and the leptonic decays of the vector bosons at the NNLO level

Summary

Introduction

We report on the first computation of the next-to-next-to-leading order (NNLO) QCD corrections to W ±Z production in proton collisions. The computation of the relevant one-loop helicity amplitudes [10] enabled the first complete NLO calculations [11,12,13], including spin correlations and off-shell effects.

Results

Conclusion