Search for Supersymmetry in pp Collisions at √s = 7 TeV in Events with Two Photons and Missing Transverse Energy


A search for supersymmetry in the context of general gauge-mediated (GGM) breaking with the lightest neutralino as the next-to-lightest supersymmetric particle and the gravitino as the lightest is presented. The data sample corresponds to an integrated luminosity of 36 pb-1 recorded by the CMS experiment at the LHC. The search is performed using events containing two or more isolated photons, at least one hadronic jet, and significant missing transverse energy. No excess of events at high missing transverse energy is observed. Upper limits on the signal cross section for GGM supersymmetry between 0.3 and 1.1 pb at the 95% confidence level are determined for a range of squark, gluino, and neutralino masses, excluding supersymmetry parameter space that was inaccessible to previous experiments.

Plots from the paper

Figure Abbreviated Caption
Closure_SG-GG-MC_BG-EG_EE_minJets1.pdf The full circles with error bars are for the γγ sample. The double-hatched blue band represents the contribution of the electroweak background. The single-hatched red band shows the sum of the electroweak background with the QCD MET prediction obtained from Z->ee sample. The prediction of the GGM SUSY model described in the text is shown in the plot as the solid line histogram.
Closure_SG-EG-MC_BG-EG_EE_minJets0.pdf The MET of the candidates (full circles with error bars) is compared to the QCD expectation for this spectrum from Z-> ee events (solid histogram). The Wγ and W+jet (where the jet is misidentified as a photon) contributions are shown as dashed and dash-dot histograms respectively. The hatched red band represents the sum of all expected background components
upperlimits.pdf 95% CL upper limits for the squark-gluino mass plane and for 150 GeV neutralino mass
exclusion2.pdf Exclusion contours in the squark-gluino mass plane for 50, 150, and 500 GeV neutralino masses for GGM SUSY

Tables with results

  • table_mass_limits.txt: Data points for contour lines in mass exclusion plot. Measured limits for neutralino masses 50 GeV, 150 GeV, and 500 GeV are shown.

  • table_upper_limits.txt: Data for 95% CL upper limits as a function of M(gluino) and M(squark) for neutralino masses 50 GeV, 150 GeV, and 500 GeV

  • table_acceptance.txt: Data from GGM acceptance as a function of M(gluino) and M(squark) for neutralino masses 50 GeV, 150 GeV, and 500 GeV

Link to the paper in CDS

-- YuriGershtein - 17-Jan-2011

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Topic revision: r10 - 2011-03-18 - AlexanderLedovskoy
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