Measurements of jet and photon production in pp collisions with the ATLAS Detector

Cross sections for jet and isolated photon production in pp collisions have been measured by the ATLAS collaboration at 7 and 8 TeV. Double­-differential cross sections for inclusive, di­, and tri­-jet final states are measured and compared to expectations based on next-­to­-leading order QCD calculations as well as to next­-to­-leading order Monte Carlo simulations. First LHC Run­2 results will be included if available. Cross­-sections for four­-jet production in 8 TeV pp collisions are measured differentially in a variety of kinematic variables, and are compared to a range of leading order Monce Carlo calculations as well as to state­-of­-the­-art next­-to­-leading order fixed­-order calculations. The observables studied include the momenta, masses, minimum and maximum angles between two or three jets, amongst others. Inclusive prompt photon cross sections have been measured precisely over a wide range of transverse momenta at different centre­of mass energies. These experimental results are compared to next-to-leading order QCD calculations with different models of the parton content of the proton. Several aspects of jet production in pp collisions have been measured by the ATLAS collaboration. The momentum-weighted sum of the charges of tracks associated to a jet is sensitive to the electrical charge of the parton initiating the jet. The distribution of the so­-called jet charge has been measured in dijet events using pp collision data at 8 TeV with the ATLAS detector. The measurement of the dijet azimuthal decorrelations, as well as the jet-­jet energy correlations are sensitive to the strong coupling constant. Measurements of multi­-jet systems with or without a veto on additional jets, probe QCD radiation effects. Jet shapes have been measured in ttbar events for light flavour as well as heavy flavour jets. These measurements constitute precision tests of QCD in a new energy regime. Also discuss jet properties and alpha_s