Precision measurement of forward Z boson production in proton-proton collisions at s = 13 TeV

Abstract

A precision measurement of the Z boson production cross-section at s$$ \sqrt{\mathrm{s}} $$ = 13 TeV in the forward region is presented, using pp collision data collected by the LHCb detector, corresponding to an integrated luminosity of 5.1 fb−1. The production cross-section is measured using Z → μ+μ− events within the fiducial region defined as pseudorapidity 2.0 < η < 4.5 and transverse momentum pT> 20 GeV/c for both muons and dimuon invariant mass 60 < Mμμ< 120 GeV/c2. The integrated cross-section is determined to beσZ→μ+μ−=196.4±0.2±1.6±3.9pb,$$ \sigma \left(Z\to {\mu}^{+}{\mu}^{-}\right)=196.4\pm 0.2\pm 1.6\pm 3.9\ \mathrm{pb}, $$where the first uncertainty is statistical, the second is systematic, and the third is due to the luminosity determination. The measured results are in agreement with theoretical predictions within uncertainties.