Measurement of the Drell-Yan forward-backward asymmetry and of the effective leptonic weak mixing angle in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports a highly precise measurement of the forward-backward asymmetry and the effective leptonic weak mixing angle in proton-proton collisions at 13 TeV, using CMS data to test the Standard Model.

Contribution

It provides the most precise hadron collider measurement of the effective leptonic weak mixing angle, using a large dataset and detailed angular analysis.

Findings

Measured $ ext{sin}^2 heta^ ext{lept}_ ext{eff}$ = 0.23152 ± 0.00031

Results agree with the Standard Model fit

Achieved the most precise measurement at a hadron collider

Abstract

The forward-backward asymmetry in Drell-Yan production and the effective leptonic electroweak mixing angle are measured in proton-proton collisions at $\sqrt{s}$ = 13 TeV, collected by the CMS experiment and corresponding to an integrated luminosity of 138 fb$^{-1}$. The measurement uses both dimuon and dielectron events, and is performed as a function of the dilepton mass and rapidity. The unfolded angular coefficient $A_4$ is also extracted, as a function of the dilepton mass and rapidity. Using the CT18Z set of parton distribution functions, we obtain $\sin\theta^\ell_\text{eff}$ = 0.23152 $\pm$ 0.00031, where the uncertainty includes the experimental and theoretical contributions. The measured value agrees with the standard model fit result to global experimental data. This is the most precise $\sin\theta^\ell_\text{eff}$ measurement at a hadron collider, with a precision comparable to the results obtained at LEP and SLD.