Measurement of the production of a W boson in association with a charm quark in pp collisions at sqrt(s)=7 TeV with the ATLAS detector

ATLAS COLLABORATION, G. AAD, F. MONTICELLI, ET AL

JOURNAL OF HIGH ENERGY PHYSICS

SPRINGER

Lugar: Berlin; Año: 2014 vol. 231 p. 1 - 23

1126-6708

The production of a W boson in association with a single charm quark is studied using 4.6 fb−1√of pp collision data at s = 7 TeV collected with the ATLAS detector at the Large Hadron Collider.In events in which a W boson decays to an electron or muon, the charm quark is tagged eitherby its semileptonic decay to a muon or by the presence of a charmed meson. The integrated anddifferential cross sections as a function of the pseudorapidity of the lepton from the W -boson decayare measured. Results are compared to the predictions of next-to-leading-order QCD calculationsobtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26 at Q2 = 1.9 GeV2 , which supports the−0.30hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-sectionratio σ(W + + c)/σ(W − + c) is compared to the predictions obtained using parton distribution functionparameterisations with different assumptions about the s?s quark asymmetry.