Download or read book Search for Scalar Top Quarks and Higgsino Like Neutralinos written by Takuya Nobe and published by Springer. This book was released on 2015-11-30 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reports a search for theoretically natural supersymmetry (SUSY) at the Large Hadron Collider (LHC). The data collected with the ATLAS detector in 2012 corresponding to 20 /fb of an integrated luminosity have been analyzed for stop pair production in proton–proton collisions at a center-of-mass energy of 8 TeV at the Large Hadron Collider (LHC) in the scenario of the higgsino-like neutralino. The author focuses on stop decaying into a bottom quark and chargino. In the scenario of the higgsino-like neutralino, the mass difference between charginos and neutralinos (Δm) is expected to be small, and observable final-state particles are likely to have low-momentum (soft). The author develops a dedicated analysis with a soft lepton as a probe of particles from chargino decay, which suppresses the large amount of backgrounds. As a result of the analysis, no significant SUSY signal is observed. The 95% confidence-level exclusion limits are set to masses of stop and neutralino assuming Δm = 20 GeV. The region with ΔM (the mass difference between stop and neutralino) 70 GeV is excluded for the first time at stop mass of less than 210 GeV. The author also excludes the signals with ΔM 120 GeV up to 600 GeV of stop mass with neutralino mass of less than 280 GeV. The author clearly shows very few remaining parameter spaces for light stop (e.g., topology of stop decay is extremely similar to the SM top quark) by combining his results and previous ATLAS analyses. His results provide a strong constraint to searches for new physics in the future.

Download or read book Search for Charginos Nearly Mass Degenerate with the Lightest Neutralino written by Shingo Kazama and published by Springer. This book was released on 2015-10-22 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, the anomaly mediated supersymmetry breaking (AMSB) model is explored by searching for charged winos with their subsequent decays collected with the ATLAS detector at the Large Hadron Collider (LHC). The author develops a new method, called “re-tracking,” to detect charged winos that decay before reaching the Semiconductor Tracker (SCT) detector. Because the nominal tracking algorithm at the ATLAS experiment requires at least seven successive hits in the inner tracking system, the sensitivity to charged winos having a fraction of a nanosecond in the past analysis was therefore limited. However, re-tracking requires a minimum of three pixel hits and provides a fully efficient tracking capability for charged winos traversing the pixel detector, resulting in around about 100 times greater efficiency for charged winos with a lifetime ~0.2 ns longer than that in past searches. Signal topology is characterized by a jet with large transverse momentum (pT), large missing transverse energy, and a high-pT disappearing track. There are three types of back ground tracks: interacting hadron tracks, charged leptons, and tracks with mismeasured pT. A background estimation based on the Monte Carlo (MC) simulation suffers from large uncertainties due to poor statistics and has difficulty simulating the properties of background tracks. Therefore, a data-driven approach has been developed by the author of the book to estimate the background track-pT spectrum. No significant excess above the background expectation is observed for candidate tracks with large transverse momentum, and constraints on the AMSB model are obtained. The author shows that in the AMSB model, a charged wino mass below 270 GeV is excluded at 95 % confidence level, which also directly constrains the mass of wino dark matter.

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 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 Perspectives On Supersymmetry Ii written by Gordon Kane and published by World Scientific. This book was released on 2010-04-14 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supersymmetry is at an exciting stage of development. It extends the Standard Model of particle physics into a more powerful theory that both explains more and allows more questions to be addressed. Most importantly, it opens a window for studying and testing fundamental theories at the Planck scale. Experimentally we are finally entering the intensity and energy and sensitivity regions where superpartners and supersymmetric dark matter candidates are likely to be detected, and then studied. There has been progress in understanding the remarkable physics implications of supersymmetry, including the derivation of the Higgs mechanism, the unification of the Standard Model forces, cosmological connections such as a candidate for the cold dark matter of the universe and consequences for understanding the cosmological history of the universe, and more.This volume begins with an excellent pedagogical introduction to the physics and methods and formalism of supersymmetry which is accessible to anyone with a basic knowledge of the Standard Model of particle physics. Next is an overview of open questions, followed by chapters on topics such as how to detect superpartners and tools for studying them, the current limits on superpartner masses as we enter the LHC era, the lightest superpartner as a dark matter candidate in thermal and non-thermal cosmological histories, and associated Z' physics. Most chapters have been extended and updated from the earlier edition and some are new.This superb book will allow interested physicists to understand the coming experimental and theoretical progress in supersymmetry and the implications of discoveries of superpartners, and will also help students and workers to quickly learn new aspects of supersymmetry they want to pursue.

Download or read book Electroweak Gauginos with Highly Boosted Hadronically Decaying Bosons at the LHC written by Yuta Okazaki and published by Springer Nature. This book was released on 2023-01-01 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supersymmetry (SUSY) introduces superpartners of the Standard Model (SM) particles. If their masses are typically O(100 GeV) ∼ O(TeV), a lightest neutralino can be a candidate for the dark matter, and the problem is solved by canceling the correction of the Higgs boson mass. Further, SUSY can explain the experimental result of the muon magnetic moment (g-2). This book presents a search for electroweakinos—the superpartners of the SM electroweak bosons—such as charginos and neutralinos using data at the LHC collected by the ATLAS detector. Pair-produced electroweakinos decay into the light ones and SM bosons (W/Z/h), and with the large mass difference between the heavy and light electroweakinos, the SM bosons have high momenta. In a fully hadronic final state, quarks decayed from the bosons are collimated, and can consequently be reconstructed as a single large-radius jet. This search has three advantages. The first is a statistical benefit by large branching ratios of the SM bosons. The second is to use characteristic signatures—the mass and substructure—of jets to identify as the SM bosons. The last is a small dependency on the signal model by targeting all the SM bosons. Thanks to them, the sensitivity is significantly improved compared to the previous analyses. Exclusion limits at the 95% confidence level on the heavy electroweakino mass parameter are set as a function of the light electroweakino mass parameter. They are set on wino or higgsino production models with various assumptions, such as the branching ratio of their decaying and the type of lightest SUSY particle. These limits are the most stringent limits. Besides, this book provides the most stringent constraints on SUSY scenarios motivated by the dark matter, the muon g-2 anomaly, and the naturalness.

Download or read book International Europhysics Conference on High Energy Physics written by Daniel Lellouch and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 1293 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 1997 International Europhysics Conference on High Energy Physics was held at the campus of the Hebrew University of Jerusalem and at the Jerusalem Renaissance Hotel, from August 19th to August 25th, 1997. This was the first time that the European Physical Society had its High Energy Physics Conference outside the boundary of Europe. A total of 550 physicists participated in the conference with a total of 250 presentations in the parallel sessions and 26 presentations in the plenary sessions. The Board of the of the High Energy and Particle Physics division (HEPP) of the EPS acted as the Scientific Organizing Committee. The Board acknowl edges the help of the International Advisory Committee as well as that of the Local Organizing Committee. The conference was co-organized by the Hebrew University of Jerusalem and by the Weizmann Institute of Science, with important help by physi cists from the Israeli Institute of Technology (Technion) and the Tel Aviv University.

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 Proceedings Of The 28th International Conference On High Energy Physics In 2 Volumes written by Zygmunt Ajduk and published by World Scientific. This book was released on 1997-04-11 with total page 1878 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 28th conference from the Rochester series was the major high energy physics conference in 1996. Volume one contains short reports on new theoretical and experimental results. Volume two consists of the review talks presented in the plenary sessions.

Download or read book Phenomena Beyond the Standard Model What Do We Expect for New Physics to Look Like written by Roman Pasechnik and published by Frontiers Media SA. This book was released on 2020-09-03 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

Download or read book Electroweak Physics at the Large Hadron Collider with the ATLAS Detector written by Elodie Resseguie and published by Springer Nature. This book was released on 2020-11-03 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis discusses searches for electroweakly produced supersymmetric partners of the gauge and the Higgs bosons (gauginos and higgsinos) decaying to multiple leptons, using pp collisions at sqrt(s) = 13 TeV. The thesis presents an in-depth study of multiple searches, as well as the first 13 TeV cross section measurement for the dominant background in these searches, WZ production. Two searches were performed using 36.1/fb of data: the gaugino search, which makes use of a novel kinematic variable, and the higgsino search, which produced the first higgsino limits at the LHC. A search using 139/fb of data makes use of a new technique developed in this thesis to cross check an excess of data above the background expectation in a search using a Recursive Jigsaw Reconstruction technique. None of the searches showed a significant excess of data, and limits were expanded with respect to previous results. These searches will benefit from the addition of luminosity during HL-LHC; however, the current detector will not be able to withstand the increase in radiation. Electronics for the detector upgrade are tested and irradiated to ensure their performance.

Download or read book Particle Physics Ideas and Recent Developments written by Jean-Jacques Aubert and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt: For more than 25 years the Standard Model of particle physics has withstood the confrontation with experimental results of increasing precision, but this does not imply that the Standard Model can answer all questions about the ultimate constituents of nature. This book presents a critical examination of the latest experimental results and confronts them with the predictions of the Standard Model. Besides discussions of accelerator results from LEP, HERA and the TEVATRON, attention is paid to the unresolved problems of neutrino oscillations, CP violation, dark matter and cosmology. New theoretical ideas are also analyzed in order to explore possible extensions of the standard model. Realistic plans for future accelerators are presented and their physics potential is discussed, paving the way for the next generation of particle physics experiments.

Download or read book Deep Inelastic Scattering written by Masahiro Kuze and published by World Scientific. This book was released on 2007 with total page 996 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings present the most up-to-date status of deep inelastic scattering (DIS) physics. Topics such as structure function measurements and phenomenology, quantum chromodynamics (QCD) studies in DIS and photoproduction, spin physics and diffractive interactions are reviewed in detail, with emphasis on those studies that push the test of QCD and the Standard Model to the limits of their present range of validity, towards both the very high and the very low four-momentum transfers in lepton-proton scattering.

Download or read book Supersymmetry Supergravity And Supercolliders Tasi 1997 written by Jonathon A Bagger and published by World Scientific. This book was released on 1999-03-12 with total page 788 pages. Available in PDF, EPUB and Kindle. Book excerpt: In June 1997, fifty-seven of the world's best students gathered at TASI '97 in Boulder, Colorado, USA, to attend an intensive series of lectures on the theory and phenomenology of supersymmetry, supergravity and supercolliders. This book contains the proceedings of that school. It is aimed at advanced graduate students as well as postdoctoral and other researchers. It provides a snapshot of the state-of-the-art in an active area of high energy particle theory, and may perhaps serve as a preview of physics to be discovered in the next decade.

Download or read book Physics In Collison Proceedings Of The Xvii International Conf written by Helen F Heath and published by World Scientific. This book was released on 1998-04-30 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: 50 years after the discovery of the pion in Bristol, the conference “Physics in Collision XVII” showed how far particle physics has come. There were hints of new physics at HERA and neutrino oscillations as well as the latest results from LEP and the Tevatron. The proceedings present the current status and future direction of particle physics.

Download or read book Dark Side Of The Universe The Experimental Efforts And Theoretical Framework Proceedings Of The Second Workshop written by Rita Bernabei and published by World Scientific. This book was released on 1996-10-22 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: The search for dark matter is one of the most relevant topics in astroparticle physics today. It involves many different experimental techniques that should collectively contribute significantly to the identification of the nature and characteristics of the dark matter constituents, offering at the same time much room for new technological developments. The theoretical framework is also essential, both for properly interpreting the different results and for suggesting the most interesting possible candidates and search strategies. This book compares the methods, the developments and the results.

Download or read book Electroweak Symmetry Breaking And New Physics At The Tev Scale written by Timothy L Barklow and published by World Scientific. This book was released on 1997-05-05 with total page 749 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an expanded version of the report by the Electroweak Symmetry Breaking and Beyond the Standard Model Working Group which was contributed to Particle Physics — Perspectives and Opportunities, a report of the Division of Particles and Fields Committee for Long Term Planning. One of the Working Group's primary goals was to study the phenomenology of electroweak symmetry breaking and attempt to quantify the “physics reach” of present and future colliders. Their investigations encompassed the Standard Model — with one doublet of Higgs scalars — and approaches to physics beyond the Standard Model. These include models of low-energy supersymmetry, dynamical electroweak symmetry breaking, and a variety of extensions of the Standard Model with new particles and interactions. The Working Group also considered signals of new physics in precision measurements arising from virtual processes and examined experimental issues associated with the study of electroweak symmetry breaking and the search for new physics at present and future hadron and lepton colliders.This volume represents an important contribution to the efforts being made to advance the frontiers of particle physics.