Measurement of double-differential charged-current Drell-Yan cross-sections at high transverse masses in pp collisions at SQUARE ROOTs = 13 TeV with the ATLAS detector

Abstract

his paper presents a first measurement of the cross-section for the chargedcurrentDrell-Yan process pp RIGHTWARDS ARROW W+- RIGHTWARDS ARROW ℓ+-ν above the resonance region, where ℓ is an electronor muon. The measurement is performed for transverse masses, mWT, between 200 GeVand 5000 GeV, using a sample of 140 fb-1 of pp collision data at a centre-of-mass energy ofSQUARE ROOTs = 13TeV collected by the ATLAS detector at the LHC during 2015-2018. The data arepresented single differentially in transverse mass and double differentially in transverse massand absolute lepton pseudorapidity. A test of lepton flavour universality shows no significantdeviations from the Standard Model. The electron and muon channel measurements arecombined to achieve a total experimental precision of 3% at low mWT. The single- and doubledifferential W-boson charge asymmetries are evaluated from the measurements. A comparisonto next-to-next-to-leading-order perturbative QCD predictions using several recent partondistribution functions and including next-to-leading-order electroweak effects indicates thepotential of the data to constrain parton distribution functions. The data are also used toconstrain four fermion operators in the Standard Model Effective Field Theory formalism,in particular the lepton-quark operator Wilson coefficient c(3)ℓq .