Speaker
Description
We present an improved extraction of the effective leptonic weak mixing angle, $\sin^2\theta^\ell_{\mathrm{eff}}$, based on the published CMS measurement of the forward–backward asymmetry ($A_{\rm FB}$) in Drell–Yan dilepton production at a center-of-mass energy of 13 TeV. The published CMS extraction already reduces parton distribution function (PDF) uncertainties by profiling with the dilepton mass dependence of $A_{\rm FB}$, yet the total uncertainty remains dominated by PDFs. We further reduce the PDF uncertainty by extending the profiling to include additional CMS measurements of the $W$-boson charge asymmetry and the $W/Z$ fiducial cross-section ratios. This extended profiling yields a substantially reduced total uncertainty, resulting in , $\sin^2\theta^\ell_{\mathrm{eff}}$ = 0.23156$\pm$0.00024, which is in excellent agreement with the Standard Model prediction of 0.23161$\pm$0.00004 and constitutes the most precise single determination of $\sin^2\theta^\ell_{\mathrm{eff}}$ to date. In the profiling process with the CMS 13 TeV measurements of $A_{\rm FB}$, $W$-boson charge asymmetry and the $W/Z$ fiducial cross-section ratio we also obtain improved determination of Parton Distribution Functions.
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