AQCD analysis is reported of ATLAS data on inclusive W-+/- and Z boson production in pp collisions at the LHC, jointly with ep deep-inelastic scattering data from HERA. The ATLAS data exhibit sensitivity to the light quark sea composition and magnitude at Bjorken x similar to 0:01. Specifically, the data support the hypothesis of a symmetric composition of the light quark sea at low x. The ratio of the strange-to-down sea quark distributions is determined to be 1:00(-0:28)(+0.25) at absolute four-momentum transfer squared Q(2) = 1: 9 GeV2 and x = 0: 023. RI Moorhead, Gareth/B-6634-2009; Fazio, Salvatore /G-5156-2010; Livan, Michele/D-7531-2012; Alexa, Calin/F-6345-2010; Takai, Helio/C-3301-2012; Doyle, Anthony/C-5889-2009; semprini cesari, nicola/G-7817-2012; Petrucci, Fabrizio/G-8348-2012; Smirnov, Sergei/F-1014-2011; Wemans, Andre/A-6738-2012; Jones, Roger/H-5578-2011; Ferrando, James/A-9192-2012; Fabbri, Laura/H-3442-2012; Villa, Mauro/C-9883-2009; de Groot, Nicolo/A-2675-2009; valente, paolo/A-6640-2010; Delmastro, Marco/I-5599-2012

Determination of the Strange-Quark Density of the Proton from ATLAS Measurements of the W -> lv and Z -> ll Cross Sections