UC Santa Cruz

A search for supersymmetry with a diphoton plus ETmiss final state is conducted using 4.8 fb-1 of collision data collected by the ATLAS detector at a center-of-mass energy of sqrt(s) = 7TeV at the LHC in 2011. At least two photon candidates with ET > 50GeV are required, and in addition three separate signal regions are defined which are geared towards high-mass gluino or squark production decaying to a high-mass neutralino, high-mass gluino or squark production decaying to a low-mass neutralino, and direct gaugino production. Each of the three signal regions is optimized for sensitivity to the targeted scenario by tuning requirements on ETmiss, HT, and DeltaPhi between the photon and the ETmiss. The Standard Model contribution is estimated using data-driven methods, and no significant excess above Standard Model expectations is observed in any of the

signal regions.

This lack of an excess is interpreted in two different flavors of gauge mediated

supersymmetry breaking. In the case of general gauge mediation with a bino-like lightest

neutralino, gluino masses up to 1070 GeV are excluded at 95% CL where the lightest

neutralino mass is between 50 GeV and the gluino mass. Squark masses are also excluded

in this model up to 910 GeV at 95% CL for lightest neutralino masses between 50 GeV and the squark mass. The SPS8 benchmark slope, a minimal gauge mediation model, is also considered and Lambda, which is the effective scale at which supersymmetry is broken, up to 197 TeV is excluded at 95% CL.