Search for Supersymmetry with Diphoton Events in 7 TeV pp Collisions at the Compact Muon Solenoid

Graduate Thesis Or Dissertation

Citations

Citeable URL: https://scholar.colorado.edu/concern/graduate_thesis_or_dissertations/nk322d37w

Abstract

This dissertation describes the search for General Gauge Mediated (GGM) supersymmetry breaking in 7 TeV center-of-mass proton-proton collisions from the Large Hadron Collider (LHC); the total integrated luminosity of data analyzed was 35.5 ± 3.9 pb-1 from the 2010 data taking. In GGM scenarios, a pair of supersymmetric particles is formed through strong production; each is expected to decay into jets, a photon, and a gravitino. Hence, searches for events with two photons and at least one jet were carried out; one observed event with missing transverse energy (MET) > 50 GeV was found. This is consistent within statistical fluctuations of the predicted Standard Model background from QCD and EW sources, 1.11±0.76 events. For one set of GGM parameters, the predicted cross-section (in leading order and next-to-leading order) is 2.309±0.413 pb, leading to a predicted number of events with MET > 50 GeV of 17.1±3.7. Given the number of observed events and the expected background, an upper limit cross section of 0.558 pb was set and the model point was excluded. Upper limit calculations and exclusion regions were calculated for gluino and squark masses of 400 − 2000 GeV and neutralino masses of 50 GeV, 150 GeV, and 500 GeV.

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