Measurements of the W boson rapidity, helicity, double-differential cross sections, and charge asymmetry in pp collisions at $\sqrt{s} =$ 13 TeV

TL;DR

This paper reports detailed measurements of W boson production, decay, and charge asymmetry at 13 TeV using CMS data, providing insights into proton structure and testing the Standard Model.

Contribution

It presents the first comprehensive set of measurements of W boson rapidity, helicity, and differential cross sections at 13 TeV, constraining parton distribution functions.

Findings

Measured W boson rapidity and charge asymmetry with high precision.

Provided double-differential cross sections as functions of lepton transverse momentum and pseudorapidity.

Constrained proton parton distribution functions using the new data.

Abstract

The differential cross section and charge asymmetry for inclusive W boson production at $\sqrt{s} =$ 13 TeV is measured for the two transverse polarization states as a function of the W boson absolute rapidity. The measurement uses events in which a W boson decays to a neutrino and either a muon or an electron. The data sample of proton-proton collisions recorded with the CMS detector at the LHC in 2016 corresponds to an integrated luminosity of 35.9 fb$^{-1}$. The differential cross section and its value normalized to the total inclusive W boson production cross section are measured over the rapidity range $|y_\mathrm{W}|$ $\lt$ 2.5. In addition to the total fiducial cross section, the W boson double-differential cross section, d$^2\sigma$/d$p^\ell_\mathrm{T}$d$|\eta|$ and the charge asymmetry are measured as functions of the charged lepton transverse momentum and pseudorapidity. The precision of these measurements is used to constrain the parton distribution functions of the proton using the next-to-leading order NNPDF3.0 set.