Measurement of the inclusive Z cross section via decays to tau pairs in pp collisions at root s=7 TeV

Abstract

The first measurement of inclusive Z → τ + τ − production in pp collisions at the LHC is presented, in the final states μ + hadrons, e + hadrons, e + μ, and μ + μ. The data sample corresponds to an integrated luminosity of 36 pb−1 collected with the CMS detector. The measured cross section is σ (pp → ZX) × B (Z → τ + τ −) = 1.00 ± 0.05(stat.) ± 0.08(syst.) ± 0.04(lumi.)nb, which is in good agreement with the next-to-next-to-leading order QCD prediction and improves on previous measurements in the Z → e+e− and μ + μ − channels. The reconstruction efficiency for hadronic τ decays is determined with a precision of 7%.