Proton-proton collisions at √ s = 7 TeV and heavy ion collisions at √ s NN = 2.76 TeV were produced by the LHC and recorded using the ATLAS experiment's trigger system in 2010. The LHC is designed with a maximum bunch crossing rate of 40 MHz and the ATLAS trigger system is designed to record approximately 200 of these per second. The trigger system selects events by rapidly identifying signatures of muon, electron, photon, tau lepton, jet, and B meson candidates, as well as using global event signatures, such as missing transverse energy. An overview of the ATLAS trigger system, the evolution of the system during 2010 and the performance of the trigger system components and selections based on the 2010 collision data are shown. A brief outline of plans for the trigger system in 2011 is presented.

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The χ(b)(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider at sqrt[s] = 7  TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4  fb(-1), these states are reconstructed through their radiative decays to Υ(1S,2S) with Υ → μ+ μ-. In addition to the mass peaks corresponding to the decay modes χ(b)(1P,2P) → Υ(1S)γ, a new structure centered at a mass of 10.530 ± 0.005(stat) ± 0.009(syst)  GeV is also observed, in both the Υ(1S)γ and Υ(2S)γ decay modes. This structure is interpreted as the χ(b)(3P) system.

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