Measurement of Wγ and Zγ production in pp collisions at s=7 TeV

Abstract

A measurement of W? and Z? production in proton?proton collisions at ?s = 7 TeV is presented. Re- sults are based on a data sample recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 36 pb?1. The electron and muon decay channels of the W and Z are used. The total cross sections are measured for photon transverse energy E? T > 10 GeV and spatial separation from charged leptons in the plane of pseudorapidity and azimuthal angle R( , ? ) > 0.7, and with an ad- ditional dilepton invariant mass requirement of M > 50 GeV for the Z? process. The following cross section times branching fraction values are found: ? (pp ? W? + X) × B(W ? ?) = 56.3 ± 5.0(stat.) ± 5.0(syst.) ± 2.3(lumi.) pb and ? (pp ? Z? + X) × B(Z ? ) = 9.4 ± 1.0(stat.) ± 0.6(syst.) ± 0.4(lumi.) pb. These measurements are in agreement with standard model predictions. The first limits on anomalous WW? , ZZ? , and Z? ? trilinear gauge couplings at ?s = 7 TeV are set.