First measurement of jets and missing transverse energy with the ATLAS calorimeter at $\sqrt{s}=900$ GeV and $\sqrt{s}=7$ TeV

In December 2009, ATLAS recorded the first proton-proton collisions delivered by the LHC at a center-of-mass energy of sqsnineh, and at sqsseven beginning in March 2010. We report on the first measurements of the kinematic distributions of jets and missing transverse energy at both center-of-mass regimes. These data also provide the opportunity test the inputs to jet reconstruction and the jet calibration schemes available in ATLAS. In addition, basic jet properties such as the number of associated charged particles, the longitudinal and radial shower topology in jets, and the transverse energy profiles of jets are compared to that expected from Monte Carlo simulations of the full detector response. We show that the basic inputs to jet reconstruction and calibration are generally well modeled by Monte Carlo simulations coupled with full detector simulation and that discrepancies will help to guide future Monte Carlo tunings and detector response descriptions.