Download or read book Search for Supersymmetry in P Anti p Collisions at S 1 2 written by and published by . This book was released on 2008 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Search for Supersymmetry in P Anti p Collisions at S written by and published by . This book was released on 2008 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Search for Supersymmetry Using Diphoton Events in P Anti p Collisions at a Center of Mass Energy of 1 96 TeV written by and published by . This book was released on 2010 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents the results of a search for supersymmetry in proton-antiproton collisions with a center of mass energy of 1.96 TeV studied with the Collider Detector at Fermilab. Our strategy is to select collisions with two photons in the final state that have the properties of being the decays of very massive supersymmetric particles. This includes looking for large total energy from the decayed particles as well as for the presence of particles that leave the detector without interacting. We find no events using 2.6 fb−1 of data collected during the 2004-2008 collider run of the Fermilab Tevatron which is consistent with the background estimate of 1.4 ± 0.4 events. Since there is no evidence of new particles we set cross section limits in a gauge-mediated supersymmetry model with {tilde {chi}}1° → [gamma]{tilde G}, where the {tilde {chi}}1° and {tilde G} are the lightest neutralino and the gravitino (the lightest supersymmetric particle), respectively. We set limits on models as a function of the {tilde {chi}}1° mass and lifetime, producing the world's most sensitive search for {tilde {chi}}1° by excluding masses up to 149 GeV/c2 for {tilde {chi}}1° lifetimes much less than 1 ns.

Download or read book Search for Supersymmetry in pp Collisions at s 8 TeV with a Photon Lepton and Missing Transverse Energy written by Yutaro Iiyama and published by Springer. This book was released on 2017-06-14 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Ph.D. thesis is a search for physics beyond the standard model (SM) of particle physics, which successfully describes the interactions and properties of all known elementary particles. However, no particle exists in the SM that can account for the dark matter, which makes up about one quarter of the energy-mass content of the universe. Understanding the nature of dark matter is one goal of the CERN Large Hadron Collider (LHC). The extension of the SM with supersymmetry (SUSY) is considered a promising possibilities to explain dark matter. The nominated thesis describes a search for SUSY using data collected by the CMS experiment at the LHC. It utilizes a final state consisting of a photon, a lepton, and a large momentum imbalance probing a class of SUSY models that has not yet been studied extensively. The thesis stands out not only due to its content that is explained with clarity but also because the author performed more or less all aspects of the thesis analysis by himself, from data skimming to limit calculations, which is extremely rare, especially nowadays in the large LHC collaborations.

Download or read book Search for Supersymmetry in Pp Collisions at Sqrt s written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Results are reported from a search for supersymmetric particles in proton-proton collisions in the final state with a single, high transverse momentum lepton; multiple jets, including at least one b-tagged jet; and large missing transverse momentum. The data sample corresponds to an integrated luminosity of 2.3 inverse-femtobarns at sqrt(s) = 13 TeV, recorded by the CMS experiment at the LHC. The search focuses on processes leading to high jet multiplicities, such as gluino pair production with gluinos to t-tbar neutralino[1]. The quantity M[J], defined as the sum of the masses of the large-radius jets in the event, is used in conjunction with other kinematic variables to provide discrimination between signal and background and as a key part of the background estimation method. The observed event yields in the signal regions in data are consistent with those expected for standard model backgrounds, estimated from control regions in data. Exclusion limits are obtained for a simplified model corresponding to gluino pair production with three-body decays into top quarks and neutralinos. Gluinos with a mass below 1600 GeV are excluded at a 95% confidence level for scenarios with low neutralino[1] mass, and neutralinos with a mass below 800 GeV are excluded for a gluino mass of about 1300 GeV. For models with two-body gluino decays producing on-shell top squarks, the excluded region is only weakly sensitive to the top squark mass.

Download or read book Search for Supersymmetry with Photons in Pp Collisions at sqrt s written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Two searches for physics beyond the standard model in events containing photons are presented. Our data sample used corresponds to an integrated luminosity of 19.7 fb-1 of proton-proton collisions at √s=8 TeV, collected with the CMS experiment at the CERN LHC. The analyses pursue different inclusive search strategies. One analysis requires at least one photon, at least two jets, and a large amount of transverse momentum imbalance, while the other selects events with at least two photons and at least one jet, and uses the razor variables to search for signal events. The background expected from standard model processes is evaluated mainly from data. These results are interpreted in the context of general gauge-mediated supersymmetry, with the next-to-lightest supersymmetric particle either a bino- or wino-like neutralino, and within simplified model scenarios. Upper limits at the 95% confidence level are obtained for cross sections as functions of the masses of the intermediate supersymmetric particles.

Download or read book Search for Supersymmetry in the All hadronic Final State Using Top Quark Tagging in Pp Collisions at Sqrt s written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search is presented for supersymmetry in all-hadronic events with missing transverse momentum based on tagging of top quarks. The data sample corresponds to an integrated luminosity of 2.3 inverse femtobarns of proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC. Search regions are defined using the properties of reconstructed jets, the presence of bottom and top quark candidates, and an imbalance in transverse momentum. With no statistically significant excess of events observed beyond the expected contributions from the standard model, we set exclusion limits at 95% confidence level on the masses of new particles in the context of simplified models of direct and gluino-mediated top squark production. For direct top squark production with decays to a top quark and a neutralino, top squark masses up to 740 GeV and neutralino masses up to 240 GeV are excluded. Gluino masses up to 1550 GeV and neutralino masses up to 900 GeV are excluded for models of gluino pair production where each gluino decays to a top-antitop quark pair and a neutralino.

Download or read book Search for Supersymmetry in P p Collisions at s written by Kin Ho Lo and published by . This book was released on 2018 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The thesis describes a search for new physics in form of supersymmetry in hadronic final states and missing transverse energy (ET) using a dataset of 35.9 fb−1 collected during the 2016 proton-proton runs by the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC). The search uses robust kinematic variables to suppress backgrounds while maintaining good acceptance to a broad range of signal models and employs data-driven techniques to accurately determine backgrounds and systematic uncertainties. No evidence for Beyond Standard Model (BSM) physics is observed and simplified models are used to interpret the results. For gluino mediated models, the gluino mass up to 1850 GeV and the lightest symmetric particle (LSP) up to 1100 GeV are excluded. For light squark mediated models, the light squark mass up to 1350 GeV (700 GeV) and the LSP up to 650 GeV (400 GeV), assuming no degeneracy in the light squark masses (a degeneracy in light squark masses). For sbottom mediated models, the sbottom mass is excluded to 1075 GeV and the LSP mass up to 550 GeV. For stop mediated models, the stop mass is excluded up to 1075 GeV with the LSP mass up to 400 GeV."--Page x.

Download or read book Search for Supersymmetry in Events with One Lepton and Multiple Jets in Proton proton Collisions at Sqrt s written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for supersymmetry is performed in events with a single electron or muon in proton-proton collisions at a center-of-mass energy of 13 TeV. The data were recorded by the CMS experiment at the LHC and correspond to an integrated luminosity of 2.3 inverse femtobarns. Several exclusive search regions are defined based on the number of jets and b-tagged jets, the scalar sum of the jet transverse momenta, and the scalar sum of the missing transverse momentum and the transverse momentum of the lepton. The observed event yields in data are consistent with the expected backgrounds from standard model processes. The results are interpreted using two simplified models of supersymmetric particle spectra, both of which describe gluino pair production. In the first model, each gluino decays via a three-body process to top quarks and a neutralino, which is associated with the observed missing transverse momentum in the event. Gluinos with masses up to 1.6 TeV are excluded for neutralino masses below 600 GeV. In the second model, each gluino decays via a three-body process to two light quarks and a chargino, which subsequently decays to a W boson and a neutralino. The mass of the chargino is taken to be midway between the gluino and neutralino masses. In this model, gluinos with masses below 1.4 TeV are excluded for neutralino masses below 700 GeV.

Download or read book Search for Supersymmetry in the Vector boson Fusion Topology in Proton proton Collisions at Sqrt s written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Our first search for supersymmetry in the vector-boson fusion topology is presented. The search targets final states with at least two leptons, large missing transverse momentum, and two jets with a large separation in rapidity. The data sample corresponds to an integrated luminosity of 19.7 fb-1 of proton-proton collisions at [arrow]" = 8 TeV collected with the CMS detector at the CERN LHC. The observed dijet invariant mass spectrum is found to be consistent with the expected standard model prediction. Upper limits are set on the cross sections for chargino and neutralino production with two associated jets, assuming the supersymmetric partner of the [tau] lepton to be the lightest slepton and the lightest slepton to be lighter than the charginos. For a compressed-mass-spectrum scenario in which the mass difference between the lightest supersymmetric particle X~01 and the next lightest, mass-degenerate, gaugino particles X~02 and X~"1 is 50 GeV, a mass lower limit of 170 GeV is set for these latter two particles.

Download or read book Search for Supersymmetry with a Photon a Lepton and Missing Transverse Momentum in Pp Collisions at sqrt s written by and published by . This book was released on 2015 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our search for supersymmetry involving events with at least one photon, one electron or muon, and large missing transverse momentum has been performed by the CMS experiment. The data sample corresponds to an integrated luminosity of 19.7 fb-1 of pp collisions at √ s = 8 TeV, produced at the CERN LHC. No excess of events is observed beyond expectations from standard model processes. The result of the search is interpreted in the context of a general model of gauge-mediated supersymmetry breaking, where the charged and neutral winos are the next-to-lightest supersymmetric particles. Within this model, winos with a mass up to 360 GeV are excluded at the 95% confidence level. Also, two simplified models inspired by gauge-mediated supersymmetry breaking are also examined, and used to derive upper limits on the production cross sections of specific supersymmetric processes.

Download or read book A Search for Supersymmetry in Events with a Z Boson Jets and Missing Transverse Energy in Pp Collisions with Sqrt s written by Tova Ray Holmes and published by . This book was released on 2016 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for new phenomena in final states containing a Z boson decaying to electrons or muons, jets, and large missing transverse momentum is presented. This search uses proton--proton collision data collected during 2015 and 2016 at a center of mass energy sqrt(s)=13 TeV by the ATLAS detector at the Large Hadron Collider, which correspond to an integrated luminosity of 14.7 fb-1. The search targets the pair production of supersymmetric particles, squarks or gluinos, which decay via jets and a Z boson to the lightest Supersymmetric particle, which does not interact with the ATLAS detector. Results are interpreted in simplified models of gluino-pair (squark-pair) production, and provide sensitivity to gluinos (squarks) with masses as large as 1.3 (1.0) TeV.

Download or read book Search for Supersymmetry in Hadronic Final States with Missing Transverse Energy Using the Variables alpha T and B quark Multiplicity in Pp Collisions at sqrt s written by and published by . This book was released on 2013 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: An inclusive search for supersymmetric processes that produce final states with jets and missing transverse energy is performed in pp collisions at a centre-of-mass energy of 8 TeV. The data sample corresponds to an integrated luminosity of 11.7 fb-1 collected by the CMS experiment at the LHC. In this search, a dimensionless kinematic variable, [alpha] T, is used to discriminate between events with genuine and misreconstructed missing transverse energy. The search is based on an examination of the number of reconstructed jets per event, the scalar sum of transverse energies of these jets, and the number of these jets identified as originating from bottom quarks. No significant excess of events over the standard model expectation is found. Exclusion limits are set in the parameter space of simplified models, with a special emphasis on both compressed-spectrum scenarios and direct or gluino-induced production of third-generation squarks. For the case of gluino-mediated squark production, gluino masses up to 950-1125 GeV are excluded depending on the assumed model. Finally, for the direct pair-production of squarks, masses up to 450 GeV are excluded for a single light first- or second-generation squark, increasing to 600 GeV for bottom squarks.

Download or read book Search for Supersymmetric Particles in Pp Collision at S written by Ping Hu and published by . This book was released on 1990 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Search for Supersymmetry in Events with a Lepton a Photon and Large Missing Transverse Energy in Pp Collisions at Sqrt s written by and published by . This book was released on 2011 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search is performed for an excess of events, over the standard model expectations, with a photon, a lepton, and large missing transverse energy in pp collisions at sqrt(s) = 7 TeV. Such events are expected in many new physics models, in particular a supersymmetric theory that is broken via a gauge-mediated mechanism, when the lightest charged and neutral gauginos are mass degenerate. The data sample used in this search corresponds to an integrated luminosity of 35 inverse picobarns collected with the CMS detector at the LHC. No evidence of such an excess above the standard model backgrounds, dominated by W-gamma production, is found. The results are presented as 95% confidence level upper limits on the cross section for a benchmark gauge-mediated scenario, and are then converted into exclusion limits on the squark, gluino, and wino masses.

Download or read book Search for Supersymmetry in Events with Soft Leptons Low Jet Multiplicity and Missing Transverse Energy in Proton u2013 proton Collisions at sqrt s written by and published by . This book was released on 2016 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results are presented from a search for supersymmetric particles in scenarios with a compressed mass spectrum. The data sample corresponds to 19.7 inverse femtobarns of proton-proton collisions recorded by the CMS experiment at √s = 8 TeV. The search targets top squark ($ ilde{t}$ pair production in scenarios with mass differences ?m = m($ ilde{t}$ – m($ ilde{i}$10) below the W-boson mass and with top-squark decays in the four-body mode ($ ilde{t}$ → blv$ ilde{i}$10), where the ($ ilde{i}$10) is assumed to be the lightest supersymmetric particle (LSP). The signature includes a high transverse momentum (pT) jet associated with initial-state radiation, one or two low-pT leptons, and significant missing transverse energy. The event yields observed in data are consistent with the expected background contributions from standard model processes. Limits are set on the cross section for top squark pair production as a function of the $ ilde{t}$ and LSP masses. Assuming a 100% branching fraction for the four-body decay mode, top-squark masses below 316 GeV are excluded for ?m = 25 GeV at 95% CL. Furthermore, the dilepton data are also interpreted under the assumption of chargino-neutralino production, with subsequent decays to sleptons or sneutrinos. Assuming a difference between the common $ ilde{i}$1+/$ ilde{i}$2+ mass and the LSP mass of 20 GeV and a ?-enriched decay scenario, masses in the range m( $ ilde{i}$1+)

Download or read book Search for Supersymmetry with Razor Variables in Pp Collisions at sqrt s written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, 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 √s = 7 TeV collected with the CMS detector at the LHC in 2011, corresponding to an integrated luminosity of 4.7 fb-1. 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 standard 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.