Dijet and Multijet cross sections measurements in ATLAS

Jet production in proton-proton collisions is a sensitive probe of several QCD effects. Measurements are presented of multijet cross sections, and of the azimuthal correlation between dijets, which are sensivitive to higher or QCD effects. Measurements of dijets separated by large intervals of rapidity are also presented, where a veto is applied based on the presence of further jets with the rapidity interval. The measurements are compared to NLO QCD and higher multiplictity LO QCD calculations matched to parton showers using leading-logarithmic approximations in the scale, Q2. The large rapidity-interval distributions are also compared to calculations using approximations based on resumming the leading-logarithmic terms in rapidity.