Abstract
The razor approach to search for R-parity conserving supersymmetric particles is described in detail. Two analyses are considered: an inclusive search for new heavy particle pairs decaying to final states with at least two jets and missing transverse energy, and a dedicated search for final states with at least one jet originating from a bottom quark. For both the inclusive study and the study requiring a bottom-quark jet, the data are examined in exclusive final states corresponding to all-hadronic, single-lepton, and dilepton events. The study is based on the data set of proton-proton collisions at sqrt(s) = 7 TeV collected with the CMS detector at the LHC in 2011, corresponding to an integrated luminosity of 4.7 inverse femtobarns. The study consists of a shape analysis performed in the plane of two kinematic variables, denoted MR and R2, that correspond to the mass and transverse energy flow, respectively, of pair-produced, heavy, new-physics particles. The data are found to be compatible with the background model, defined by studying event simulations and data control samples. Exclusion limits for squark and gluino production are derived in the context of the constrained minimal supersymmetric model (CMSSM) and also for simplified-model spectra (SMS). Within the CMSSM parameter space considered, squark and gluino masses up to 1350 GeV are excluded at 95% confidence level, depending on the model parameters. For SMS scenarios, the direct production of pairs of top or bottom squarks is excluded for masses as high as 400 GeV.
Highlights
Extensions of the standard model (SM) with softly broken supersymmetry (SUSY) [1,2,3,4,5] predict new fundamental particles that are superpartners of the SM particles
The presence of multiple interactions per crossing was taken into account in the CMS Monte Carlo (MC) simulation by adding a random number of minimum bias events to the hard interactions, with the multiplicity distribution matching that in data
Reconstructed muons are not included in the megajet grouping because, unlike electrons, they are distinguished from jets in the high-level trigger (HLT)
Summary
Extensions of the standard model (SM) with softly broken supersymmetry (SUSY) [1,2,3,4,5] predict new fundamental particles that are superpartners of the SM particles. Under the assumption of R-parity [6] conservation, searches for SUSY particles at the Fermilab Tevatron [7,8] and the CERN LHC [9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25] have focused on event signatures with energetic hadronic jets and leptons from the decays of pair-produced squarks q~ and gluinos g~ Such events frequently have large missing transverse energy (EmT iss) resulting from the stable weakly interacting superpartners, one of which is produced in each of the two decay chains. For the SMS, limits are provided in terms of the masses of the produced SUSY partner and the LSP
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