An NLO QCD effective field theory analysis of $W^+_{}W^-_{}$ production at the LHC including fermionic operators

TL;DR

This paper analyzes how anomalous gauge boson and fermion couplings affect W+W- production at the LHC, highlighting the importance of QCD corrections and the limitations of the dimension-6 EFT approximation at high transverse momentum.

Contribution

It provides a detailed helicity amplitude analysis and demonstrates the breakdown of the dimension-6 EFT approximation at high energies in W+W- production.

Findings

QCD corrections significantly influence anomalous coupling fits.

Dimension-6 EFT fails at p_T around 500-1000 GeV.

Helicity amplitudes clarify new physics contributions.

Abstract

We study the impact of anomalous gauge boson and fermion couplings on the production of $W^+W^-$ pairs at the LHC. Helicity amplitudes are presented separately to demonstrate the sources of new physics contributions and the impact of QCD and electroweak corrections. The QCD corrections have important effects on the fits to anomalous couplings, in particular when one $W$ boson is longitudinally polarized and the other is transversely polarized. In effective field theory language, we demonstrate that the dimension-6 approximation to constraining new physics effects in $W^+W^-$ pair production fails at $p_T\sim 500-1000$ GeV.