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Title: Measurement of associated W + charm production in pp collisions at $$\sqrt{s}$$ = 7 TeV

Measurements are presented of the associated production of a W boson and a charm-quark jet (W + c) in pp collisions at a center-of-mass energy of 7 TeV. The analysis is conducted with a data sample corresponding to a total integrated luminosity of 5 inverse femtobarns, collected by the CMS detector at the LHC. W boson candidates are identified by their decay into a charged lepton (muon or electron) and a neutrino. The W + c measurements are performed for charm-quark jets in the kinematic region $$p_T^{jet} \gt$$ 25 GeV, $$|\eta^{jet}| \lt$$ 2.5, for two different thresholds for the transverse momentum of the lepton from the W-boson decay, and in the pseudorapidity range $$|\eta^{\ell}| \lt$$ 2.1. Hadronic and inclusive semileptonic decays of charm hadrons are used to measure the following total cross sections: $$\sigma(pp \to W + c + X) \times B(W \to \ell \nu)$$ = 107.7 +/- 3.3 (stat.) +/- 6.9 (syst.) pb ($$p_T^{\ell} \gt$$ 25 GeV) and $$\sigma(pp \to W + c + X) \times B(W \to \ell \nu)$$ = 84.1 +/- 2.0 (stat.) +/- 4.9 (syst.) pb ($$p_T^{\ell} \gt$$ 35 GeV), and the cross section ratios $$\sigma(pp \to W^+ + \bar{c} + X)/\sigma(pp \to W^- + c + X)$$ = 0.954 +/- 0.025 (stat.) +/- 0.004 (syst.) ($$p_T^{\ell} \gt$$ 25 GeV) and $$\sigma(pp \to W^+ + \bar{c} + X)\sigma(pp \to W^- + c + X)$$ = 0.938 +/- 0.019 (stat.) +/- 0.006 (syst.) ($$p_T^{\ell} \gt$$ 35 GeV). Cross sections and cross section ratios are also measured differentially with respect to the absolute value of the pseudorapidity of the lepton from the W-boson decay. These are the first measurements from the LHC directly sensitive to the strange quark and antiquark content of the proton. Results are compared with theoretical predictions and are consistent with the predictions based on global fits of parton distribution functions.
Authors:
 [1]
  1. et al.
Publication Date:
OSTI Identifier:
1151673
Report Number(s):
FERMILAB-PUB--13-632-CMS; CERN-PH-EP--2013-149; CMS-SMP--12-002
Journal ID: ISSN 1029-8479; arXiv eprint number arXiv:1310.1138
Grant/Contract Number:
AC02-07CH11359
Type:
Accepted Manuscript
Journal Name:
Journal of High Energy Physics (Online)
Additional Journal Information:
Journal Name: Journal of High Energy Physics (Online); Journal Volume: 2014; Journal Issue: 2; Journal ID: ISSN 1029-8479
Publisher:
Springer Berlin
Research Org:
Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Orgs:
CMS Collaboration
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS