Determination of proton parton distribution functions using ATLAS data

We present fits to determine parton distribution functions (PDFs) using inclusive W/Z-boson measurements from the ATLAS experiment at the LHC. The ATLAS measurements are used in combination with deep-inelastic scattering data from HERA. We also present the results of PDF fits that use W/Z+jets measurements from ATLAS in addition to the measurements listed above. An improved determination of the sea-quark densities at high Bjorken, x, is seen, while confirming a strange-quark density similar in size to the up- and down-sea-quark densities in the range x < 0.02 found by previous ATLAS analyses.