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 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 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 Events with at Least One Photon and Missing Transverse Momentum in Proton proton Collisions at a Center of mass Energy of 13 TeV at the CMS Experiment written by Johannes Schulz and published by . This book was released on 2018* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Search for Supersymmetry in Proton proton Collisions at 7 TeV in Events with a Single Lepton B tagged Jets and Missing Transverse Momentum at the LHC Using Data Collected from the CMS Detector written by Wing Howard To and published by . This book was released on 2013 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes a search for supersymmetry (SUSY) at the Large Hadron Collider using data collected in Run 2011 at center of mass energy of 7 TeV by the Compact Muon Solenoid detector with an integrated luminosity of 4.98 $fb{-1}$. First, the Large Hadron Collider is briefly described along with the Compact Muon Solenoid detector. Second, the Standard Model of particle physics is described which leads to the motivations for supersymmetry and its description. Finally, a search for supersymmetry in events with a single lepton, 2 b-tagged jets and missing transverse energy is documented in detail. The results are used to predict the yields from the standard model in bins missing transverse energy (\met) and total transverse hadronic energy (HT). Limits are set using these results using a minimal supergravity SUSY model and simplified model spectra SUSY model.

Download or read book Search for Supersymmetry in Proton proton Collisions at 8 TeV in Events with a Single Lepton Large Jet Multiplicity and Multiple B Jets written by Paul B. Geffert and published by . This book was released on 2014 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes a search for supersymmetry in events with a single lepton, large jet multiplicity, multiple b jets, and significant transverse momentum imbalance in 19.3 fb-1 of pp collisions at center of mass energy of 8 TeV recorded in 2012 by the Compact Muon Solenoid experiment at the Large Hadron Collider. This signature targets strongly produced massive gluinos which decay through top squarks. The observed yields in the signal regions, spanning a broad range of event kinematics, agree with the Standard Model background predictions, which are obtained with a heavy reliance on data control samples. The results of this search are interpreted as cross section limits in the context of simplified supersymmetric scenarios in which gluinos are pair produced and cascade decay to a four top quark, two lightest neutralino final state. By comparing these limits with gluino pair production cross sections, gluinos with mass less than 1 TeV are excluded for low lightest neutralino masses, largely independent of top squark mass.

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 Gauge Mediated SUSY Breaking in Diphoton Events in Proton Anti proton Collisions at S 1 2 written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present the results of a search for anomalous production of diphoton events with large missing transverse energy using the Collider Detector at Fermilab. In 202 pb[sup -1] of p[bar p] collisions at [radical]s = 1.96 TeV they observe no candidate events, with an expected standard model background of 0.27 [+-] 0.07(stat) [+-] 0.10(syst) events. The results exclude a lightest chargino of mass less than 167 GeV/c[sup 2], and lightest neutralino of 93 GeV/c[sup 2] at 95% confidence level in a gauge-mediated supersymmetry-breaking model with a light gravitino.

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: A search for supersymmetry in hadronic final states with highly boosted W bosons and b jets is presented, focusing on compressed scenarios. The search is performed using proton-proton collision data at a center-of-mass energy of 8 TeV, collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 19.7 fb$^{-1}$. Events containing candidates for hadronic decays of boosted W bosons are identified using jet substructure techniques, and are analyzed using the razor variables $M_\mathrm{R}$ and $R^2$, which characterize a possible signal as a peak on a smoothly falling background. The observed event yields in the signal regions are found to be consistent with the expected contributions from standard model processes, which are predicted using control samples in the data. The results are interpreted in terms of gluino pair production followed by their exclusive decay into top squarks and top quarks. The analysis excludes gluino masses up to 1.1 TeV for light top squarks decaying solely to a charm quark and a neutralino, and up to 700 GeV for heavier top squarks decaying solely to a top quark and a neutralino.

Download or read book Search for Gauge Mediated SUSY Breaking in Diphoton Events in Proton Anti proton Collisions at S 1 2 written by Min Suk Kim and published by . This book was released on 2004 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present the results of a search for anomalous production of diphoton events with large missing transverse energy using the Collider Detector at Fermilab. In 202 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV they observe no candidate events, with an expected standard model background of 0.27 {+-} 0.07(stat) {+-} 0.10(syst) events. The results exclude a lightest chargino of mass less than 167 GeV/c{sup 2}, and lightest neutralino of 93 GeV/c{sup 2} at 95% confidence level in a gauge-mediated supersymmetry-breaking model with a light gravitino.

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 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 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 in Proton proton Collisions at a Center of mass Energy of 13 Tev with a Customized Top Quark Tagger in the All hadronic Final State written by Hua Wei and published by . This book was released on 2017 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a search for direct and gluino-mediated production of supersymmetric scalar top-quark pairs in the all-hadronic final state using top tagging. The result of search is based on a 13 TeV proton-proton sample collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 36 fb-1. The results of the search are interpreted in several Simplified Models (SMS).

Download or read book Search for Supersymmetry in Pp Collisions at 7 TeV in Events with Jets and Missing Transverse Energy written by and published by . This book was released on 2011 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for supersymmetry with R-parity conservation in proton-proton collisions at a centre-of-mass energy of 7 TeV is presented. The data correspond to an integrated luminosity of 35 inverse picobarns collected by the CMS experiment at the LHC. The search is performed in events with jets and significant missing transverse energy, characteristic of the decays of heavy, pair-produced squarks and gluinos. The primary background, from standard model multijet production, is reduced by several orders of magnitude to a negligible level by the application of a set of robust kinematic requirements. With this selection, the data are consistent with the standard model backgrounds, namely t t-bar, W + jet and Z + jet production, which are estimated from data control samples. Limits are set on the parameters of the constrained minimal supersymmetric extension of the standard model. These limits extend those set previously by experiments at the Tevatron and LEP colliders.

Download or read book Search for Supersymmetry in 8 TeV Proton proton Collision Events with Bottom quark Jets and Missing Transverse Energy written by Benjamin Kreis and published by . This book was released on 2014 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for supersymmetry in a sample of proton-proton collision events with a center-of-mass energy of 8 TeV is presented. The sample, collected with the Compact Muon Solenoid detector at the Large Hadron Collider, corresponds to an integrated luminosity of 19.4 fb[-]1 . Events are required to have large missing transverse energy, at least three jets, and at least one identified bottom-quark jet. Numbers of events in exclusive bins of the scalar sum of jet transverse momentum values, missing transverse energy, and bottom-quark jet multiplicity are found to be consistent with the standard model expectations. The results are interpreted as 95% confidence level upper limits on simplified supersymmetric models approximating gluino mediated bottom- and top-squark production.

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.