Download or read book Searching for Supersymmetry with Same sign Di leptons Using the Cms Experiment at the Large Hadron Collider written by Ronald C. Remington and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: After imposing the event selection requirements that define the signal region, 1 event is observed, which is statistically consistent with the total expected Standard Model background rate of 0.80 ± 0.33. Given this lack of an excess, exclusion limits are calculated on the parameter space of SUSY models with universal gaugino and scalar mass scales. The general limit on cross-section [delta] multiplied by branching ratio BR and the event selection acceptance A[superscript experiment] is [sigma] x BR x A[superscript experiment]
Download or read book Searching for Supersymmetry with Tri Leptons and Missing Transverse Energy Using the CMS Experiment at the Large Hadron Collider written by Nikoloz Skhirtladze and published by . This book was released on 2013 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, we target supersymmetry scenarios where the colored superpartners are assumed to be heavy (and decoupled). We consider the possibility of light sleptons, giving rise to pp ..., where the decays to leptons are mediated by intermediate on-shell sleptons. We also consider the possibility that the sleptons are heavy, leaving only three-body decays through Standard Model W's and Z's. An extensive overview of the data-driven methods used to model the behavior of background processes is given as well. This analysis focuses on this type of direct electroweak supersymmetry production, and we set further constraints on the masses of chargino and neutralino particles.
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 the One Lepton Channel at the LHC written by Arun Preston Luthra and published by . This book was released on 2013 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for supersymmetry was performed in events with one electron or muon, jets, and missing transverse momentum. The dataset was the first 5.0 fb [superscript -1] of [Square root of s] = 7 TeV proton-proton events from the Large Hadron Collider, as measured by the CMS detector in 2011. A data-driven method was used to estimate the background at high values of the transverse mass, where the suppression of the Standard Model backgrounds allows for relatively loose cuts on the jet activity. No excess above the expected background was observed, so a limit was set in the m0- m[subscript 1/2] plane of the CMSSM at tan [Beta] = 10, A0 = 0, and sgn(mu) = +1.
Download or read book Supersymmetry Beyond Minimality written by Shaaban Khalil and published by CRC Press. This book was released on 2017-12-06 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supersymmetry (SUSY) is one of the most important ideas ever conceived in particle physics. It is a symmetry that relates known elementary particles of a certain spin to as yet undiscovered particles that differ by half a unit of that spin (known as Superparticles). Supersymmetric models now stand as the most promising candidates for a unified theory beyond the Standard Model (SM). SUSY is an elegant and simple theory, but its existence lacks direct proof. Instead of dismissing supersymmetry altogether, Supersymmetry Beyond Minimality: from Theory to Experiment suggests that SUSY may exist in more complex and subtle manifestation than the minimal model. The book explores in detail non-minimal SUSY models, in a bottom-up approach that interconnects experimental phenomena in the fermionic and bosonic sectors. The book considers with equal emphasis the Higgs and Superparticle sectors, and explains both collider and non-collider experiments. Uniquely, the book explores charge/parity and lepton flavour violation. Supersymmetry Beyond Minimality: from Theory to Experiment provides an introduction to well-motivated examples of such non-minimal SUSY models, including the ingredients for generating neutrino masses and/or relaxing the tension with the heavily constraining Large Hadron Collider (LHC) data. Examples of these scenarios are explored in depth, in particular the discussions on Next-to-Minimal Supersymmetric SM (NMSSM) and B-L Supersymmetric SM (BLSSM).
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 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 A Search for Supersymmetry with Same sign Tau and Lepton Final States at the CMS Experiment written by Arlo Emrys Guneratne Bryer and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dileptons and Jets at the LHC written by Christopher Edward Justus and published by . This book was released on 2012 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: The thesis presents the results from two searches using dileptons and jetsbased on 4.98 fb-1 of data taken by the CMS experiment at the Large HadronCollider during the 2011 run. The first is part of a larger, complete search forsupersymmetry using the signal of one isolated lepton, jets and missing transverseenergy. Although the search concentrates on a single lepton topology, this thesisoutlines the procedure to predict the contribution from dilepton events which, through various processes, feed down into the single lepton control sample. Thesecond is a search for massive, exotic, colored fermions decaying to two jets and alepton by looking for a peak in the lepton plus two jet invariant mass spectrum. Adata-driven method has been developed in order to make a background prediction. The observations are consistent with the standard model background prediction. The results are presented as limits on the cross section of such exotic fermions asa function of mass.
Download or read book Search for Supersymmetry in Hadronic Final States written by Hannsjörg Artur Weber and published by Springer. This book was released on 2015-06-11 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: The project reported here was a search for new super symmetric particles in proton-proton collisions at the LHC. It has produced some of the world’s best exclusion limits on such new particles. Furthermore, dedicated simulation studies and data analyses have also yielded essential input to the upgrade activities of the CMS collaboration, both for the Phase-1 pixel detector upgrade and for the R&D studies in pursuit of a Phase-2 end cap calorimeter upgrade.
Download or read book Search for Supersymmetry in Final States with Leptons with the ATLAS Detector at the Large Hadron Collider written by and published by . This book was released on 2013 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: After a short review of the Standard Model of Elementary Particle Physics and its minimal supersymmetric extension, the MSSM, a global analysis of two highly simplified supersymmetric models, the CMSSM and the NUHM1 is presented, with a focus on the fine-tuning of these models. A new, phenomenologically motivated measure for fine-tuning is introduced. In addition, a search for supersymmetry in final states with four leptons is presented, where a procedure for the consideration of trigger efficiencies with a focus on the calculation of uncertainties on the sum of event weights is given. Fina...
Download or read book Beyond Standard Model Collider Phenomenology of Higgs Physics and Supersymmetry written by Marc Christopher Thomas and published by Springer. This book was released on 2016-08-01 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis studies collider phenomenology of physics beyond the Standard Model at the Large Hadron Collider (LHC). It also explores in detail advanced topics related to Higgs boson and supersymmetry – one of the most exciting and well-motivated streams in particle physics. In particular, it finds a very large enhancement of multiple Higgs boson production in vector-boson scattering when Higgs couplings to gauge bosons differ from those predicted by the Standard Model. The thesis demonstrates that due to the loss of unitarity, the very large enhancement for triple Higgs boson production takes place. This is a truly novel finding. The thesis also studies the effects of supersymmetric partners of top and bottom quarks on the Higgs production and decay at the LHC, pointing for the first time to non-universal alterations for two main production processes of the Higgs boson at the LHC–vector boson fusion and gluon–gluon fusion. Continuing the exploration of Higgs boson and supersymmetry at the LHC, the thesis extends existing experimental analysis and shows that for a single decay channel the mass of the top quark superpartner below 175 GeV can be completely excluded, which in turn excludes electroweak baryogenesis in the Minimal Supersymmetric Model. This is a major new finding for the HEP community. This thesis is very clearly written and the introduction and conclusions are accessible to a wide spectrum of readers.
Download or read book Supersymmetry Search in Multilepton Final States with Taus Using the CMS Detector at the LHC written by Sho Maruyama and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents a search for SUperSYmmetry (SUSY) in multilepton final states with a data set corresponding to 34.9 pb−1 collected in 2010 with the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) running at a center-of-mass energy of 7 TeV. The analysis channels contain combinations of at least three leptons: electrons, muons, and hadronically decaying taus that are reconstructed using a particle-flow technique. The minimal SUperGRAvity (mSUGRA) model and co-Next-to-the-Lightest-SUSY-Particle (co-NLSP) scenario in the Gauge-Mediated SUSY Breaking (GMSB) model are considered. To identify SUSY signal events, signal and Standard Model (SM) background processes are studied with full detector simulation and systematics uncertainties are evaluated. Relevant SM backgrounds include Z boson + jets, diboson, tt, and QCD processes. The separation between the signal and background is performed using a cut-based selection. Good agreement between simulated samples and data is obtained, in particular for the significant Z boson + jets background. With the chosen event selection, we observe three events in data, consistent with the SM predic- tion within statistical fluctuations. Therefore, we set exclusion limits on both models using Bayesian statistics. For the SUSY parameters of m0 = 60 GeV, A0 = 0, tan[beta] = 3, and [mu]> 0, chargino masses below 163 GeV are excluded in the mSUGRA model. In GMSB, gluino masses up to 1040 GeV are excluded in co-NLSP scenario.
Download or read book Search for Supersymmetry in Final States with Two Same Sign Leptons Or Three Leptons and Jets with the ATLAS Detector at the LHC written by Othmane Rifki and published by . This book was released on 2017 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Search for Displaced Leptons in the ATLAS Detector written by Lesya Horyn and published by Springer Nature. This book was released on 2022-02-07 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a search for long-lived particles decaying into displaced electrons and/or muons with large impact parameters. This signature provides unique sensitivity to the production of theoretical lepton-partners, sleptons. These particles are a feature of supersymmetric theories, which seek to address unanswered questions in nature. The signature searched for in this thesis is difficult to identify, and in fact, this is the first time it has been probed at the Large Hadron Collider (LHC). It covers a long-standing gap in coverage of possible new physics signatures. This thesis describes the special reconstruction and identification algorithms used to select leptons with large impact parameters and the details of the background estimation. The results are consistent with background, so limits on slepton masses and lifetimes in this model are calculated at 95% CL, drastically improving on the previous best limits from the Large Electron Positron Collider (LEP).
Download or read book The Search for Supersymmetry in Hadronic Final States Using Boosted Object Reconstruction written by Giordon Holtsberg Stark and published by . This book was released on 2018 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Large Hadron Collider (LHC) operates at the highest energy scales ever artificially created in particle collision experiments with a center-of-mass energy √s = 13 TeV. In addition, the high luminosity allows the unique opportunity to probe the Standard Model at the electroweak scale and explore for rare signs of new physics beyond the Standard Model. The coupling of the third-generation top quark to the Higgs boson introduces large, quadratic, radiative corrections to the Higgs mass, requiring a significant amount of fine-tuning that results in a nearly perfect correction of the Higgs mass from the Planck scale to the observable electroweak scale. A possible solution to the naturalness problem proposes a collection of supersymmetric partners to the Standard Model particles with the mass of lightest particles at the electroweak scale: the gluino, the stop squarks, and the lightest supersymmetric particle. This thesis presents the results of a search for gluino pair production decaying via stop squarks to the lightest neutralino in hadronic final states using a total integrated luminosity 36.1 fb‒1 of data collected with the ATLAS detector in 2015 and 2016. This analysis considers a simplified supersymmetry model targeting extreme regions of the phase space with large missing transverse momentum, multiple b-tagged jets, and several energetic jets. No excess is observed and limits on the gluino mass are set at the 95% CL, greatly extending the previous results in 2012 from 1.4 TeV to 1.9 TeV. The increase of the LHC luminosity also poses challenges to the current trigger system in the ATLAS detector necessitating planned upgrades. One of the upgrades for the trigger system is the Global Feature Extractor (gFEX) which aims to recover lost efficiency in boosted hadronic final states by identifying large radius jets produced by top quarks, Higgs, Z and W bosons which are critical for future ATLAS physics programs. This module is a unique board with 3 processor FPGAs for data processing and an embedded multi-processor system-on-chip for slow-control and monitoring. This thesis will also describe the work on developing this hardware and several physics upgrade studies on the trigger performance.
Download or read book Search for Supersymmetry in Opposite sign Dilepton Final States Including Tau Leptons with the CMS Experiment written by and published by . This book was released on 2014 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
