Abstract
Abstract Results of searches for heavy stable charged particles produced in pp collisions at $ \sqrt{s} $ = 7 and 8 TeV are presented corresponding to an integrated luminosity of 5.0 fb−1 and 18.8 fb−1, respectively. Data collected with the CMS detector are used to study the momentum, energy deposition, and time-of-flight of signal candidates. Leptons with an electric charge between e/3 and 8e, as well as bound states that can undergo charge exchange with the detector material, are studied. Analysis results are presented for various combinations of signatures in the inner tracker only, inner tracker and muon detector, and muon detector only. Detector signatures utilized are long time-of-flight to the outer muon system and anomalously high (or low) energy deposition in the inner tracker. The data are consistent with the expected background, and upper limits are set on the production cross section of long-lived gluinos, scalar top quarks, and scalar τ leptons, as well as pair produced long-lived leptons. Corresponding lower mass limits, ranging up to 1322 GeV/c2 for gluinos, are the most stringent to date.
Highlights
Background predictionCandidates passing the preselection criteria are subject to two additional selection criteria to further improve the signal-to-background ratio
Masses below 935 (818) GeV/c2 are excluded for the cloud models
Drell-Yan like signals with |Q| = e/3, 2e/3, 1e, 2e, 3e, 4e, 5e, 6e, 7e, and 8e are excluded with masses below 200, 480, 574, 685, 752, 793, 796, 781, 757, and 715 GeV/c2, respectively
Summary
The searches presented here are sensitive to a wide variety of signals of new charged massive particles. The minimal gauge-mediated supersymmetry breaking (GMSB) model [35] predicts the gravitino to be the lightest supersymmetric particle (LSP) and allows for the next-tolightest supersymmetric particle (NLSP) to be long-lived because of the weakness of the gravitational coupling, which governs the decay of the NLSP to the LSP For this analysis the NLSP is taken to be a lepton-like stau (τ1) wi√th an assumed lifetime that exceeds the time-of-flight through the CMS detector. The last of the signal samples studied is the modified Drell-Yan production of longlived leptons In this scenario, new massive spin-1/2 particles may have an electric charge different than |Q| = 1e and are neutral under SU(3)C and SU(2)L; they couple only to the photon and the Z boson v√ia U(1) couplings [51]. The CTEQ6L1 parton distribution functions (PDF) [52] are used for the sample generation
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