Factorization of the forward-backward charge asymmetry and measurements of the weak mixing angle and proton structure at hadron colliders

TL;DR

This paper introduces a novel method to simultaneously extract the weak mixing angle and proton structure information from the forward-backward charge asymmetry at hadron colliders, aiming for high-precision, model-independent measurements.

Contribution

The paper proposes a new approach to factorize proton structure effects and jointly determine the weak mixing angle and PDFs from AFB data, improving precision over traditional methods.

Findings

A set of structure parameters for proton information is defined.

A new fitting method for simultaneous parameter extraction is proposed.

The approach highlights the need for additional observations to reduce uncertainties.

Abstract

The forward-backward charge asymmetry (AFB) at hadron colliders is sensitive to both the electroweak (EW) symmetry breaking represented by the effective weak mixing angle, and the proton structure information in the initial state modeled by the parton distribution functions (PDFs). Due to their strong correlation, the precisions of the determination on the weak mixing angle and PDFs using the measured AFB spectrum are limited. In this paper, we define a set of structure parameters which factorize the unique proton information of the relative difference between quarks and antiquarks in the AFB observation. Other than the conventional way of extracting the weak mixing angle fro the convolution of PDF and EW calculations, we propose a new method to simultaneously determine the value of the weak mixing angle and the proton structure terms by fitting to the observed AFB distribution, and point out the necessity of specifying additional observations to further reduce the uncertainties on the proton structure terms respectively, so that the model-independent high precision measurements can be achieved at the future LHC experiments.