A measurement of the cross section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy ffiffi ffi s p ¼ 7 TeV is presented. The measurement covers the pseudorapidity ranges j j < 1:37 and 1:52 j j < 1:81 in the transverse energy range 15 E T < 100 GeV. The results are based on an integrated luminosity of 880 nb À1 , collected with the ATLAS detector at the Large Hadron Collider. Photon candidates are identified by combining information from the calorimeters and from the inner tracker. Residual background in the selected sample is estimated from data based on the observed distribution of the transverse isolation energy in a narrow cone around the photon candidate. The results are compared to predictions from next-to-leading-order perturbative QCD calculations.

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Inclusive jet and dijet cross sections have been measured in proton-proton collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the Large Hadron Collider. The cross sections were measured using jets clustered with the anti-k t algorithm with parameters R ¼ 0:4 and R ¼ 0:6. These measurements are based on the 2010 data sample, consisting of a total integrated luminosity of 37 pb À1. Inclusive jet double-differential cross sections are presented as a function of jet transverse momentum, in bins of jet rapidity. Dijet double-differential cross sections are studied as a function of the dijet invariant mass, in bins of half the rapidity separation of the two leading jets. The measurements are performed in the jet rapidity range jyj < 4:4, covering jet transverse momenta from 20 GeV to 1.5 TeV and dijet invariant masses from 70 GeV to 5 TeV. The data are compared to expectations based on next-to-leadingorder QCD calculations corrected for nonperturbative effects, as well as to next-to-leading-order Monte Carlo predictions. In addition to a test of the theory in a new kinematic regime, the data also provide sensitivity to parton distribution functions in a region where they are currently not wellconstrained.

Jet shapes have been measured in inclusive jet production in proton-proton collisions at ffiffi ffi s p ¼ 7 TeV using 3 pb À1 of data recorded by the ATLAS experiment at the LHC. Jets are reconstructed using the anti-k t algorithm with transverse momentum 30 GeV < p T < 600 GeV and rapidity in the region jyj < 2:8. The data are corrected for detector effects and compared to several leading-order QCD matrix elements plus parton shower Monte Carlo predictions, including different sets of parameters tuned to model fragmentation processes and underlying event contributions in the final state. The measured jets become narrower with increasing jet transverse momentum and the jet shapes present a moderate jet rapidity dependence. Within QCD, the data test a variety of perturbative and nonperturbative effects. In particular, the data show sensitivity to the details of the parton shower, fragmentation, and underlying event models in the Monte Carlo generators. For an appropriate choice of the parameters used in these models, the data are well described.

Differential cross sections and photon-beam asymmetries for the gamma(p)-->K{+}Lambda(1520) reaction have been measured with linearly polarized photon beams at energies from the threshold to 2.4 GeV at 0.6or=5/2 or by a new reaction process, for example, an interference effect with the phi photoproduction having a similar bump structure in the cross sections.