Impact of LHCb 13 TeV $W$ and $Z$ pseudo-data on the Parton Distribution Functions

TL;DR

This paper evaluates how future LHCb 13 TeV $W$ and $Z$ boson data can significantly improve the precision of proton parton distribution functions, especially at small-$x$, using pseudo-data simulations and the { extsc ePump} tool.

Contribution

It demonstrates the potential of LHCb 13 TeV data to substantially reduce PDF uncertainties, particularly through double-differential $Z$ boson measurements, a novel application of pseudo-data analysis.

Findings

300 fb$^{-1}$ data can greatly reduce PDF uncertainties at small-$x$

Double-differential $Z$ boson measurements are highly effective in constraining $u$ and $d$ quark PDFs

Sizable improvements in PDF accuracy are achievable with future LHCb data

Abstract

We study the potential of the LHCb 13 TeV single $W^{\pm}$ and $Z$ boson pseudo-data for constraining the parton distribution functions (PDFs) of the proton. As an example, we demonstrate the sensitivity of the LHCb 13 TeV data, collected with integrated luminosities of 5 fb$^{-1}$ and 300 fb$^{-1}$, to reducing the PDF uncertainty bands of the CT14HERA2 PDFs, using the error PDF updating package {\sc ePump}. The sensitivities of various experimental observables are compared. Generally, sizable reductions in PDF uncertainties can be observed in the 300 fb$^{-1}$ data sample, particularly in the small-$x$ region. The double-differential cross section measurement of $Z$ boson $p_T$ and rapidity can greatly reduce the uncertainty bands of $u$ and $d$ quarks in almost the whole $x$ range, as compared to various single observable measurements.