Search for Long-Lived Particles using Displaced Photons in $pp$ Collisions at sqrt(s) = 7 \TeV

The results of a search for supersymmetry are presented using long-lived particles decaying into photons and invisible particles. Events were collected at a center-of-mass energy of 7 TeV in proton-proton collisions by the CMS detector at the LHC. The search is performed in the context of gauge-mediated symmetry breaking, where the lightest neutralino can have a non zero lifetime. The missing transverse energy and the time of impact of the photon on the surface of the electromagnetic calorimeter is used to search for an excess of events over the background expectation. After the final selection, using a data set of 4.86 fb$^{-1}$ no significant excess is observed, and limits are set on the mass and proper decay length of the neutralino. Limits of 220 GeV/c$^2$ for its mass and 6000 mm on the proper decay length are set at 95 \% CL.