Impact of Lattice Strangeness Asymmetry Data in the CTEQ-TEA Global Analysis

TL;DR

This paper investigates how lattice data influences the determination of the proton's strangeness asymmetry in global PDF analyses, showing that lattice data reduces uncertainties especially at large x, and discusses implications for various experimental data sets.

Contribution

It introduces the inclusion of lattice data into the CTEQ-TEA global analysis, demonstrating improved constraints on the strangeness asymmetry PDF and analyzing parametrization dependence.

Findings

Including lattice data reduces the error band of s_- at large x.

Allowing nonzero s_- maintains fit quality comparable to previous models.

More precise lattice data at smaller x could further improve constraints.

Abstract

We study the impact of lattice data on the determination of the strangeness asymmetry distribution $s_-(x) \equiv s(x) - {\bar s}(x)$ in the general CTEQ-TEA global analysis of parton distribution functions (PDFs) of the proton. Firstly, we find that allowing a nonvanishing $s_-(x)$, at the initial $Q_0=1.3$~GeV scale, in a global PDF analysis leads to a CT18As fit with similar quality to CT18A. Secondly, including the lattice data in the CT18As\_Lat fit greatly reduces the $s_-$-PDF error band size in the large-$x$ region. To further reduce its error would require more precise lattice data, extended to smaller $x$ values. We take ATLAS 7 TeV $W$ and $Z$ production data, SIDIS di-muon production data, $F_3$ structure function data, E866 NuSea data, and E906 SeaQuest data as examples to illustrate the implication of CT18As and CT18As\_Lat fits. The parametrization dependence for PDF ratio $(s+\bar{s})/(\bar{u}+\bar{d})(x)$ is analyzed with CT18As2 and CT18As2\_Lat fits as results.