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.
Categories: hep-ex