Measurement of the Z/γ∗ → ττ cross section in pp collisions at √s = 13TeV and validation of τ lepton analysis techniques

Abstract

A measurement is presented of the Z/γ ∗ → ττ cross section in pp collisions at √ s = 13 TeV, using data recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 2.3 fb−1. The product of the inclusive cross section and branching fraction is measured to be σ(pp → Z/γ ∗+X) B(Z/γ ∗ → ττ) = 1848 ± 12 (stat) ± 67 (syst +lumi) pb, 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 futuremeasurements of τ lepton production. The measurement also provides the reconstruction efficiency and energy scale for τ decays to hadrons+ντ final states, determined with respective relative uncertainties of 2.2 and 0.9%.