W and Z boson production at CMS in pp collisions at sqrt(s)=7 TeV

The first measurements of inclusive W and Z production cross sections in muon and electron decay channels at √s = 7 TeV are reported, obtained using 198 nb⁻¹ of pp collisions in the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC). The measured inclusive cross sections are σ (pp → W + X → ℓν + X) = 9.22 ± 0.24(stat.) ± 0.47(syst.) ± 1.01(lumi.) nb, and σ (pp → Z(γ^∗) + X → ℓ⁺ℓ⁻ + X) = 0.882⁺ ₋ ⁰ ₀ ⁰⁷⁷ ₀₇₃(stat.)⁺ ₋ ⁰ ₀ ⁰⁴² ₀₃₆(syst.) ± 0.097(lumi.) nb, limited to the di-lepton invariant mass range: [60, 120] GeV/c². The luminosity-independent cross section ratios are σ (pp → W + X → ℓν + X)/σ (pp → Z(γ^∗) + X → ℓ⁺ℓ⁻ + X) = 10.46⁺ ₋ ⁰ ₀ ⁹⁹ ₈₈(stat.)⁺ ₋ ⁰ ₀ ⁶⁵ ₅₆(syst.) and σ (pp → W⁺ + X → ℓ⁺ν + X)/σ (pp → W⁻ + X → ℓ⁻ν + X) = 1.51₋ ⁺ ₀ ⁰ ₀₇ ⁰⁸(stat.) ± 0.04(syst.). The measured values agree with NNLO QCD cross section calculations and current parton distribution functions. Measurements of the W lepton charge asymmetry in three bins of pseudorapidity are also reported.