Measurement of the forward W boson cross-section in pp collisions at root s=7 TeV

LHCb collaboration

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A measurement of the inclusive W -> mu nu production cross-section using data from pp collisions at a centre-of-mass energy of root s=7 TeV is presented. The analysis is based on an integrated luminosity of about 1.0 fb(-1) recorded with the LHCb detector. Results are reported for muons with a transverse momentum greater than 20 GeV/c and pseudorapidity between 2.0 and 4.5. The W+ and W- production cross-sections are measured to besigma(W+->mu+nu)=861.0 +/- 2.0 +/- 11.2 +/- 14.7pb,sigma(W-->mu-(nu)over bar)=675.8 +/- 1.9 +/- 8.8 +/- 11.6pb,where the first uncertainty is statistical, the second is systematic and the third is due to the luminosity determination. Cross-section ratios and differential distributions as functions of the muon pseudorapidity are also presented. The ratio of W+ to W- cross-sections in the same fiducial kinematic region is determined to besigma(W+->mu+nu)/sigma(W-->mu-(nu)over bar) = 1.274 +/- 0.005 +/- 0.009,where the uncertainties are statistical and systematic, respectively. Results are in good agreement with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics.
Original languageEnglish
Article number079
Number of pages25
JournalJournal of High Energy Physics
Issue number12
Publication statusPublished - 10 Dec 2014
Externally publishedYes


  • Hadron-Hadron Scattering
  • QCD
  • Forward physics

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