Determination of electroweak parameters in polarised deep-inelastic scattering at HERA

TL;DR

This paper presents a comprehensive analysis of electroweak parameters using polarized deep-inelastic scattering data from HERA, achieving more precise measurements of the $W$ boson mass and quark couplings consistent with the Standard Model.

Contribution

It provides the first combined electroweak and QCD analysis of polarized HERA data, significantly improving the precision of key electroweak parameters.

Findings

W boson mass measured as 80.520 ± 0.115 GeV

Determined light quark couplings to Z boson

Results are consistent with Standard Model

Abstract

The parameters of the electroweak theory are determined in a combined electroweak and QCD analysis using all deep-inelastic $e^+p$ and $e^-p$ neutral current and charged current scattering cross sections published by the H1 Collaboration, including data with longitudinally polarised lepton beams. Various fits to Standard Model parameters in the on-shell scheme are performed. The mass of the $W$ boson is determined as $m(W)=80.520\pm 0.115$ GeV. The axial-vector and vector couplings of the light quarks to the $Z$ boson are also determined. Both results improve the precision of previous H1 determinations based on HERA-I data by about a factor of two. Possible scale dependence of the weak coupling parameters in both neutral and charged current interactions beyond the Standard Model is also studied. All results are found to be consistent with the Standard Model expectations.