Recent QCD results from ATLAS

The ATLAS collaborationhas performed studies of a wide range of QCD phenomena. Recent soft-QCD measurements include studies of hadronic event shapes and double-parton scattering. Dierential measurements of inclusive-jet production provide stringent tests of higher-order QCD predictions and provide input for the determination of the parton density functions. Jet-multiplicity ratios are sensitive to the strong coupling constant and have reduced sensitivity to the uncertainties due to parton distribution functions. Measurements of the inclusive isolated-photon, photon plus jet and diphoton dierential cross sections provide a direct probe of short-distance physics, complementary to that from measurements of jets or vector-bosons, and are sensitive to the gluon density of the proton.