Summary of the Precision Measurements of the Electroweak Mixing Angle in the Region of the Z pole

TL;DR

This paper reviews an improved measurement of the electroweak mixing angle using CMS data, achieving the most precise single determination to date by incorporating additional measurements to better constrain parton distribution functions.

Contribution

It introduces a novel approach of combining CMS measurements to reduce uncertainties in the effective weak mixing angle extraction.

Findings

Most precise single measurement of $oldsymbol{ heta^ ext{eff}_ ext{W}}$ to date

Reduced total uncertainty through additional PDF constraints

Result consistent with Standard Model predictions

Abstract

This contribution presents an overview of 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 in Drell-Yan events at 13 TeV [1]. While the original CMS analysis [2] achieved a significant reduction in experimental uncertainties, its overall precision remains limited by residual uncertainties in the parton distribution functions (PDFs). This proceeding highlights the impact of incorporating complementary CMS measurements that probe different combinations of parton densities, thereby providing additional PDF constraints beyond those obtained from the asymmetry measurement alone. The improved analysis leads to a substantially reduced total uncertainty, yielding $\sin^2\theta^\ell_{\mathrm{eff}} = 0.23156\pm0.00024$. This result is consistent with the Standard Model prediction and represents the most precise single determination of this parameter to date.