Performance of the Electron and Photon Trigger in p-p Collisions at sqrt(s) = 7 TeV

Events with electrons and photons (e/$\gamma$) in the final state are important signatures for many physics analyses at the LHC. In order to gain access to these events, a trigger was developed based on calorimeter and tracking information that is composed of three levels each with increasing rejection ability and decision latency, Level-1 (L1), Level-2 (L2), and Event Filter (EF). This note presents the performance of these triggers during the ATLAS data taking in 2010. Specifically, e/$\gamma$ reconstruction algorithms and selection criteria, which are based on calorimeter and tracking information, are described. The efficiency of these selections at L1, L2, and EF are presented. The performance of the e/$\gamma$ primary physics triggers is presented with respect to e/$\gamma$ reconstructed and identified by the offline software which uses slightly more sophisticated reconstruction algorithms due to less stringent timing constraints. In particular, $J/\psi \rightarrow ee$, $W \rightarrow e\nu$, and $Z \rightarrow ee$ are processes that can be used to gauge detector and trigger performance. Approximately $45\, \mbox{pb}^{-1}$ of proton-proton collision data at a centre-of-mass energy of $\sqrt{s} = 7$TeV were collected under stable beam conditions.