Determination of the parton distribution functions of the proton from ATLAS measurements of differential $W^\pm$ and $Z$ boson production in association with jets

TL;DR

This paper introduces a new set of proton parton distribution functions derived from ATLAS measurements of boson production with jets at the LHC, improving understanding of sea-quark densities at high Bjorken x.

Contribution

The paper presents ATLASepWZVjet20, a novel PDF set incorporating recent LHC and HERA data at NNLO QCD, with enhanced sea-quark density determination.

Findings

Improved high-x sea-quark density measurements

Confirmed strange-quark density comparable to up- and down-sea-quarks at low x

Provides a new PDF set for proton structure analysis

Abstract

This article presents a new set of proton parton distribution functions, ATLASepWZVjet20, produced in an analysis at next-to-next-to-leading order in QCD. The new data sets considered are the measurements of $W^+$ and $W^-$ boson and $Z$ boson production in association with jets in $pp$ collisions at $\sqrt{s} = 8~\mathrm{TeV}$ performed by the ATLAS experiment at the LHC with integrated luminosities of $20.2~\mathrm{fb}^{-1}$ and $19.9~\mathrm{fb}^{-1}$, respectively. The analysis also considers the ATLAS measurements of differential $W^{\pm}$ and $Z$ boson production at $\sqrt{s} = 7~\mathrm{TeV}$ with an integrated luminosity of $4.6~\mathrm{fb}^{-1}$ and deep-inelastic-scattering data from $e^{\pm}p$ collisions at the HERA accelerator. An improved determination of the sea-quark densities at high Bjorken $x$ is shown, while confirming a strange-quark density similar in size to the up- and down-sea-quark densities in the range $x \lesssim 0.02$ found by previous ATLAS analyses.