QCD Corrections in SMEFT Fits to $WZ$ and $WW$ Production

Abstract

We investigate the role of anomalous gauge boson and fermion couplings on the production of $WZ$ and $W^{+}{W}^{-}$ pairs at the LHC to NLO QCD in the Standard Model effective field theory, including dimension-6 operators. Our results are implemented in a publicly available version of the POWHEG-BOX. We combine our $WZ$ results in the leptonic final state $e\nu {\mu }^{+}{\mu }^{-}$ with previous $W^{+}{W}^{-}$ results to demonstrate the numerical effects of NLO QCD corrections on the limits on effective couplings derived from ATLAS and CMS 8 and 13 TeV differential measurements. Our study demonstrates the importance of including NLO QCD SMEFT corrections in the $WZ$ analysis, while the effects on $WW$ production are smaller. We also show that the $\mathcal{O}(1/{\Lambda }^4)$ contributions dominate the analysis, where $\Lambda$ is the high energy scale associated with the SMEFT.

Comments: 28 pages, 10 figures. Version accepted for publication in Phys. Rev. D