Measurements of inclusive W and Z cross sections in pp collisions at √s = 7 TeV The CMS collaboration

Politecnico di Bari, Bari, Italy
Journal of High Energy Physics (Impact Factor: 6.11). 01/2011; 2011(1):080. DOI: 10.1007/JHEP01(2011)080


Measurements of inclusive W and Z boson production cross sections in pp collisions at Ös = 7 \sqrt {s} = 7 TeV are presented, based on 2.9 pb−1 of data recorded by the CMS detector at the LHC. The measurements, performed in the electron and muon decay channels, are
combined to give

s( \textpp ® \textWX ) B( \textW ® ln ) = 9.95±0.07( \textstat. )±0.28( \textsyst. )±1.09 \sigma \left( {{\text{pp}} \to {\text{W}}X} \right) \times \mathcal{B}\left( {{\text{W}} \to \ell \nu } \right) = 9.95\pm 0.07\left( {{\text{stat}}{.}} \right)\pm 0.28\left( {{\text{syst}}{.}} \right)\pm 1.09 (lumi.) nb and

s( \textpp ® \textZX ) B( Z ® l+ l- ) = 0.931±0.026( \textstat. )±0.023( \textsyst. )±0.102 \sigma \left( {{\text{pp}} \to {\text{Z}}X} \right) \times \mathcal{B}\left( {Z \to {\ell^{+} }{\ell^{-} }} \right) = 0.931\pm 0.026\left( {{\text{stat}}{.}} \right)\pm 0.023\left( {{\text{syst}}{.}} \right)\pm 0.102 (lumi.) nb, where ℓ stands for either e or μ. Theoretical predictions, calculated at the next-to-next-to-leading order in QCD using recent parton distribution functions,
are in agreement with the measured cross sections. Ratios of cross sections, which incur an experimental systematic uncertainty
of less than 4%, are also reported.

KeywordsHadron-Hadron Scattering

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    • "• Statistical uncertainties of the simulation: The uncertainty due to the limited number of events in simulation is estimated via pseudo-experiments by varying the response matrix and the efficiency within the statistical uncertainties. • FSR: The simulation is reweighted to reflect the difference between a soft-collinear approach and the exact O(α) result, similar to what was done in Ref. [34]. It also reflects effects from higher-order contributions. "
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