Ashish Kumar – DIS 2006 – April 20-24 2006 7 Photon Identification Require :   95% of energy in EM layers  Isolation : Veto track(s) around EM cluster  Veto track(s) around EM cluster  Shower profile compatible with photon Reconstruct EM objects from energy clusters in calorimeter by cone algorithm Signal Background  Suppress most of the jet background except when single  0 or  carries most of the jet's energy : significant amount due to large jet cross section
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