Abstract
A multivariate likelihood method to measure electroweak couplings with the Drell–Yan process at the LHC is presented. The process is described by the dilepton rapidity, invariant mass, and decay angle distributions. The decay angle ambiguity due to the unknown assignment of the scattered constituent quark and antiquark to the two protons in a collision is resolved statistically using correlations between the observables. The method is applied to a sample of dimuon events from proton-proton collisions at √s=7 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 1.1 fb-1. From the dominant uu̅ , dd̅ →γ*/Z→μ-μ+ process, the effective weak mixing angle parameter is measured to be sin2θeff=0.2287±0.0020 (stat.)±0.0025 (syst.). This result is consistent with measurements from other processes, as expected within the standard model. Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. © 2011 CERN, for the CMS Collaboration