Speaker
Description
We present an improved extraction of the effective leptonic weak mixing angle based on the CMS measurement of the forward–backward asymmetry in Drell–Yan dilepton production at 13 TeV, enhanced by additional constraints from W-boson charge asymmetry and W/Z cross-section measurements. The original CMS extraction, performed with different modern parton distribution functions (PDFs), shows a one-sigma spread among the CT18, NNPDF4.0, and MSHT20 PDF sets, reflecting residual PDF uncertainties. By incorporating the complementary W and Z measurements into a combined PDF profiling framework, we significantly improve the consistency among PDF sets and reduce the overall uncertainty. The resulting determination of the effective leptonic weak mixing angle, sin²θ_eff = 0.23156 ± 0.00024, represents the most precise single measurement of this parameter to date.