The ATLAS electron, photon, tau, jet and missing transverse energy high level trigger algorithms performance with first LHC collisions
Collisions of the Large Hadron Collider (LHC) were collected by ATLAS end of 2009 at a centre of mass energy of 900 GeV and are now being collected at √s = 7 TeV. This paper gives an overview of the performance of the ATLAS high level trigger for the selection of electrons, photons, taus, jets and missing transverse energy. Comparisons of the selection variables based on the calorimeter and tracking information calculated by the different trigger levels and the offline reconstruction are shown. This has been an important step in the commissioning of these triggers to ensure their correct functioning and the results from the first data are very encouraging. Furthermore, examples of comparisons between data and Monte Carlo simulations of some of the selection variables are presented. At the end a brief outlook will be given on the steps to be taken to fully commission these triggers with 7 TeV collision data.