Download or read book Search for Supersymmetry in Di photon Final States at sqrt s written by and published by . This book was released on 2007 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report results of a search for supersymmetry (SUSY) with gauge-mediated symmetry breaking in di-photon events collected by the D0 experiment at the Fermilab Tevatron Collider in 2002-2006. In 1.1 fb-1 of data, we find no significant excess beyond the background expected from the standard model and set the most stringent lower limits to date for a standard benchmark model on the lightestneutralino and chargino masses of 125 GeV and 229 GeV, respectively, at 95% confidence.
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 Monophoton Final State at CMS at a Center of Mass Energy of 13 TeV written by De-Lin Xiong and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mission of the CMS experiment at the LHC is to investigate and discover unknown physics in proton-proton collision events. This thesis presents a search for new physics in final states containing a photon and missing transverse momentum in proton-proton collisions at $\\\\sqrt{s}$ = 13 TeV, using the data collected in Run II (2016, 2017 and 2018) by the CMS experiment at the LHC, corresponding to an integrated luminosity of 137 $\\\\text{fb}^{-1}$. The standard model (SM) background in monophoton events can be a problem for sensitivity to new physics. The sensitivity to new physics scenarios can potentially be enhanced by other event properties. A new strategy that can potentially enhance the new physics sensitivity is the track multiplicity from the small mass splitting supersymmetry (SUSY). SUSY with small mass splittings indicates the masses difference between the SUSY particles is small ($\\\\tilde{q}, squark \\\\approx \\\\tilde{\\\\chi}$, dark matter particle). The track multiplicity in monophoton dataset with different bins of track $p_T$ will be studied, and compared with expectation.
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 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 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 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 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 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 Electroweak Production with Photons and Large Missing Transverse Energy 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 supersymmetry with gauge-mediated supersymmetry breaking in electroweak production. Final states with photons and large missing transverse energy ($E_{\mathrm{T}}^{\text{miss}}$) were examined. The data sample was collected in pp collisions at $\sqrt{s} = $ 8 TeV with the CMS detector at the LHC and corresponds to 7.4 fb$^{-1}$. The analysis focuses on scenarios in which the lightest neutralino has bino- or wino-like components, resulting in decays to photons and gravitinos, where the gravitinos escape undetected. The data were obtained using a specially designed trigger with dedicated low thresholds, providing good sensitivity to signatures with photons, $E_{\mathrm{T}}^{\text{miss}}$, and low hadronic energy. No excess of events over the standard model expectation is observed. The results are interpreted using the model of general gauge mediation. With the wino mass fixed at 10 GeV above that of the bino, wino masses below 710 GeV are excluded at 95% confidence level. Constraints are also set in the context of two simplified models, for which the analysis sets the lowest cross section limits on the electroweak production of supersymmetric particles.
Download or read book A Search for Supersymmetry with New Kinematic Variables in Proton Proton Collisions at Sqrt s written by Travis Bain and published by . This book was released on 2012 with total page 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 Physics with Photons Using the ATLAS Run 2 Data written by Stefano Manzoni and published by Springer. This book was released on 2019-08-02 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work presented in this book is based on the proton-proton collision data from the Large Hadron Collider at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector in 2015 and 2016. The research program of the ATLAS experiment includes the precise measurement of the parameters of the Standard Model, and the search for signals of physics beyond the SM. Both these approaches are pursued in this thesis, which presents two different analyses: the measurement of the Higgs boson mass in the di-photon decay channel, and the search for production of supersymmetric particles (gluinos, squarks or winos) in a final state containing two photons and missing transverse momentum. Finally, ATLAS detector performance studies, which are key ingredients for the two analyses outlined before, are also carried out and described.
Download or read book Search for Supersymmetry Using Diphoton Events in Proton antiproton Collisions at a Center of Mass Energy of 1 96 TeV written by Eun Sin Lee and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents the results of a search for supersymmetry in protonantiproton 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 gaugemediated supersymmetry model with X01 ---> [gamma]G, where the X01 and G are the lightest neutralino and the gravitino (the lightest supersymmetric particle), respectively. We set limits on models as a function of the X01 mass and lifetime, producing the world's most sensitive search for X01 by excluding masses up to 149 GeV/c2 for X01 lifetimes much less than 1 ns.
Download or read book Search for Supersymmetry Using a Photon B jets and E MissT Final State with the ATLAS Detector in Proton proton Collisions at 8TeV Center of mass Energy written by and published by . This book was released on 2015 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: The result of this analysis is interpreted in a general gauge mediation framework with a lightest neutralino that is a mixture of bino and higgsino. Limits are set in a 2D plane of gluino mass vs neutralino mass. Neutralino masses between 150 GeV and 450 GeV are excluded at 95% CL for all gluino masses, and gluino masses up to at least 1200 GeV (and up to 1350 GeV in some cases) are excluded at 95% CL for neutralino masses between 450 GeV and 50 GeV less than the gluino mass.
Download or read book Search for Supersymmetry in Final States with Two Oppositely Charged Same flavor Leptons and Missing Transverse Momentum in Proton proton Collisions at s written by Albert M. Sirunyan and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
