Measurement of the cross section in pp collisions at and validation of lepton analysis techniques

A measurement is presented of the $$ cross section in $$ collisions at $$ , using data recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of $$ . The product of the inclusive cross section and branching fraction is measured to be $$ , in agreement with the standard model expectation, computed at next-to-next-to-leading order accuracy in perturbative quantum chromodynamics. The measurement is used to validate new analysis techniques relevant for future measurements of $$ lepton production. The measurement also provides the reconstruction efficiency and energy scale for $$ decays to hadrons $$ final states, determined with respective relative uncertainties of 2.2 and 0.9%.