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

• Main Author: Taylor, Frank E. (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor)
• Format: Article
• Language: English
• Published: Springer-Verlag, 2014-09-10T15:29:33Z.
• Subjects: Article
• Online Access: Get fulltext

 The production of a W boson in association with a single charm quark is studied using 4.6 fb[superscript −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 either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96[+0.26 over −0.30] at Q [superscript 2] = 1.9 GeV[superscript 2], which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W [superscript +] + [bar over c])/σ(W [superscript −] + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s − [bar over s] quark asymmetry.