Abstract
A search for diphoton events with large missing transverse momentum has been performed using proton–proton collision data at s=7 TeV recorded with the ATLAS detector, corresponding to an integrated luminosity of 4.8 fb−1. No excess of events was observed above the Standard Model prediction and model-dependent 95% confidence level exclusion limits are set. In the context of a generalised model of gauge-mediated supersymmetry breaking with a bino-like lightest neutralino of mass above 50 GeV, gluinos (squarks) below 1.07 TeV (0.87 TeV) are excluded, while a breaking scale Λ below 196 TeV is excluded for a minimal model of gauge-mediated supersymmetry breaking. For a specific model with one universal extra dimension, compactification scales 1/R<1.40 TeV are excluded. These limits provide the most stringent tests of these models to date.
Highlights
This Letter reports on a search for diphoton (γ γ ) events with large missing transverse mom√entum ( E miss T ) in4.8 fb−1 of proton–proton collision data at s = 7 TeV recorded with the ATLAS detector at the Large Hadron Collider (LHC) in 2011, extending and superseding a prior study performed with 1 fb−1 [1]
Two different configurations of the gauge-mediated supersymmetry breaking (GGM) SUSY model are considered in this study, for which the neutralino next-to-lightest SUSY particle (NLSP), chosen to be the bino, and either the gluino or the squark masses are treated as ATLAS Collaboration / Physics Letters B 718 (2012) 411–430 free parameters
After correcting for contributions from pile-up and the deposition ascribed to the photon itself, photon candidates were removed if more than 5 GeV of transverse energy was observed in a cone of ( η)2 + ( φ)2 < 0.2 surrounding the energy deposition in the calorimeter associated with the photon
Summary
This Letter reports on a search for diphoton (γ γ ) events with large missing transverse mom√entum The results are interpreted in the context of three models of new physics: a general model of gauge-mediated supersymmetry breaking (GGM) [2,3,4], a minimal model of gauge-mediated supersymmetry breaking (SPS8) [5], and a model with one universal extra dimension (UED) [6,7,8]
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