Download or read book Dark Matter Constraints on Supersymmetric Extensions of the Standard Model written by Andreas le Fevre Birkedal-Hansen and published by . This book was released on 2003 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Supersymmetric Dark Matter Candidates in Light of Constraints from Collider and Astroparticle Observables written by Jonathan Da Silva and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Standard Model of particle physics has been strengthened by the recent discovery of the long-awaited Higgs boson. The standard cosmological model has met the challenge of the high precision observations in comology and astroparticle physics. However these two standard models face both several theoretical issues, such as the naturalness problem in the Higgs sector of the Standard Model, as well as observational issues, in particular the fact that an unknown kind of matter called Dark Matter accounts for the majority of the matter content in our Universe. Attempts to solve such problems have led to the development of New Physics models during the last decades. Supersymmetry is one such model which addresses the fine-tuning problem in the Higgs sector and provides viable Dark Matter candidates. Current high energy and high precision experiments give many new opportunities to probe the supersymmetric models. It is in this context that this thesis is written. Considering the Minimal Supersymmetric Standard Model (MSSM), the simplest supersymmetric extension of the Standard Model of particle physics, and its conventional Dark Matter candidate, the neutralino, it is shown that collider constraints could provide informations on the very early Universe at the inflation area. It is also demonstrated that the Indirect Detection of Dark Matter, despite several drawbacks, can be a powerful technique to probe supersymmetric Dark Matter models. Beyond the MSSM it is shown that unique characteristics of the Dark Matter candidate in the NMSSM could be probed at colliders. The study of a supersymmetric model with an extended gauge symmetry, the UMSSM, is also developed. The features of another Dark Matter candidate of this model, the Right-Handed sneutrino, are analysed. More general constraints such as those coming from low energy observables are finally considered in this model.

Download or read book Extensions of the Standard Model with Dark Matter in Some Explicit Examples written by Mohammadreza Zakeri Niasar and published by . This book was released on 2017 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: The compelling astrophysical evidence for dark matter on one hand and the experimental evidence for neutrino masses on the other, demands modifications beyond the Standard Model. Therefore, building new models by extending the symmetries and particle content of the Standard Model is being pursued to remedy these problems. In this thesis, various models along with their predictions are presented. First, a gauge SU(2)N extension of the Standard Model, under which all of the Standard Model particles are singlet is introduced. The inverse seesaw mechanism is implemented for neutrino mass, with the new gauge boson as a dark matter candidate. The second paper is a gauge B-L extension of the Standard Model which breaks down to Z3, and it includes a long-lived dark matter candidate. The next model assumes that leptons do not couple directly to Higgs, and one loop mass generation is considered with important consequences, including Higgs decay, muon anomalous magnetic moment, etc. We then look at a U(1) gauge extension of the supersymmetric Standard Model, which has no [mu] term, and the Higgs boson's mass supersymmetric constraint is relaxed. The next model is a gauge B-L extension of the Standard Model with radiative seesaw neutrino mass and multipartite dark matter. We then consider another gauge U(1) extension under which quarks and leptons of each family may transform differently, while flavor-changing interactions are suitably suppressed. The next paper has an unbroken gauge SU(2) symmetry, which becomes confining at keV scale. We discuss the cosmological constraints and the implications for future e +e- colliders. Finally, an alternative left-right model is proposed with an automatic residual Z 2 × Z3 symmetry, such that dark matter has two components, i.e., one Dirac fermion and one complex scalar.

Download or read book Higgs Supersymmetry and Dark Matter After Run I of the LHC written by Béranger Dumont and published by Springer. This book was released on 2016-09-21 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work was nominated as an outstanding PhD thesis by the LPSC, Université Grenoble Alpes, France. The LHC Run 1 was a milestone in particle physics, leading to the discovery of the Higgs boson, the last missing piece of the so-called "Standard Model" (SM), and to important constraints on new physics, which challenge popular theories like weak-scale supersymmetry. This thesis provides a detailed account of the legacy of the LHC Run 1 ≤¥regarding these aspects. First, the SM and the need for its extension are presented in a concise yet revealing way. Subsequently, the impact of the LHC Higgs results on scenarios of new physics is assessed in detail, including a careful discussion of the relevant uncertainties. Two approaches are considered: generic modifications of the Higgs couplings, possibly arising from extended Higgs sectors or higher-dimensional operators; and tests of specific new physics models. Lastly, the implications of the null results of the searches for new physics are discussed with a particular focus on supersymmetric dark matter candidates. Here as well, two approaches are presented: the "simplified models" approach, and recasting by event simulation. This thesis stands out for its educational approach, its clear language and the depth of the physics discussion. The methods and tools presented offer readers essential practical tools for future research.

Download or read book Physics Beyond the Standard Model written by and published by . This book was released on 2008 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Standard Model (SM) of particle physics is remarkably successful and has survived two decades of precision tests at high energy particle accelerators. However, it is known to be incomplete, and there are reasons to believe that there is new physics at energy scales that will soon be probed in greater detail than ever before by the Large Hadron Collider (LHC), a proton-proton accelerator being built near Geneva. This thesis contains a diverse set of topics that may broadly be described as physics beyond the SM. In Chapter 2, implications of current experimental constraints are presented for the stop masses and mixing in the Minimal Supersymmetric Standard Model (MSSM), a well-motivated candidate for physics beyond the SM. It is found, for example, that lower bounds on the stop masses are as large as 1 TeV assuming no stop-mixing. Chapter 3 presents the regions in the MSSM with the minimal amount of fine-tuning of electroweak symmetry breaking. The minimal amount of tuning increases enormously for a Higgs mass beyond 120 GeV. Supersymmetry cannot be an exact symmetry, and one possibility is that our Universe is in a long-lived metastable state with broken supersymmetry. In Chapter 4, a generic model with this property is constructed in which all the relevant parameters, including the supersymmetry breaking scale, are generated dynamically. This model has several interesting model-building features including an explicitly and spontaneously broken R-symmetry, a singlet, a large global symmetry, naturalness, renormalizability, and a "pseudo-runaway'' direction. In Chapter 5, a simple extension of the SM with weakly interacting non-chiral dark matter particles is presented. Such particles can be detected at a future direct-detection experiment. There are a wide variety of possible discovery signatures for new physics at the LHC. A discovery signature with a large SM background that has not been well studied involves multi-jet events without leptons and/or missing energy. In Chapter 6, it is found that using innovative search strategies pair production of new coloured adjoint fermions producing a pure six-jet final state can be detected up to a mass of about 650-700 GeV with 10 fb-1 of integrated luminosity.

Download or read book Supersymmetric Dark Matter in the NMSSM and E6SSM written by Sophie Underwood and published by . This book was released on 2016 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supersymmetric extensions of the standard model may resolve the outstanding dark matter problem by producing viable dark matter candidates, including a stable weakly interacting particle called a neutralino. The next-to-minimal supersymmetric standard model (NMSSM) is first explored with a scan of the parameter space for neutralino-hadron scattering using an updated value for the strange quark sigma commutator. This is followed by an extensive exploration of the parameter space of the E6-inspired supersymmetric standard model (E6SSM). It is demonstrated that this model still provides neutralino dark matter candidates that may be detected in the near-future by upcoming experiments, despite tightening experimental constraints.

Download or read book Dark Matter Inflation and Baryogenesis in Supersymmetric Extensions of the Standard Model written by Ernestas Pukartas and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Supersymmetric Grand Unified Theories written by Stuart Raby and published by Springer. This book was released on 2017-04-29 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: These course-tested lectures provide a technical introduction to Supersymmetric Grand Unified Theories (SUSY GUTs), as well as a personal view on the topic by one of the pioneers in the field. While the Standard Model of Particle Physics is incredibly successful in describing the known universe it is, nevertheless, an incomplete theory with many free parameters and open issues. An elegant solution to all of these quandaries is the proposed theory of SUSY GUTs. In a GUT, quarks and leptons are related in a simple way by the unifying symmetry and their electric charges are quantized, further the relative strength of the strong, weak and electromagnetic forces are predicted. SUSY GUTs additionally provide a framework for understanding particle masses and offer candidates for dark matter. Finally, with the extension of SUSY GUTs to string theory, a quantum-mechanically consistent unification of the four known forces (including gravity) is obtained. The book is organized in three sections: the first section contains a brief introduction to the Standard Model, supersymmetry and the Minimal Supersymmetric Standard Model. Then SUSY GUTs in four space-time dimensions are introduced and reviewed. In addition, the cosmological issues concerning SUSY GUTs are discussed. Then the requirements for embedding a 4D SUSY GUT into higher-dimensional theories including gravity (i.e. String Theory) are investigated. Accordingly, section two of the course is devoted to discussing the so-called Orbifold GUTs and how in turn they solve some of the technical problems of 4D SUSY GUTs. Orbifold GUTs introduce a new set of open issues, which are then resolved in the third section in which it is shown how to embed Orbifold GUTs into the E(8) x E(8) Heterotic String in 10 space-time dimensions.

Download or read book Construction of Standard like String Models and Supersymmetric Neutralino Dark Matter written by Kajia Yuan and published by . This book was released on 1991 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Phenomenology of New Physics Beyond the Standard Model written by Özer Özdal and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this PhD thesis we investigate various aspects of phenomenology of new physics beyond the Standard Model (SM) in the context of extensions of supersymmetric \& non-supersymmetric realisations. In extensions of supersymmetric realisations, we first study the low scale predictions of the supersymmetric standard model extended by $U(1)_{B-L}\times U(1)_{R}$ symmetry, obtained from $SO(10)$ breaking via a left-right supersymmetric model, imposing universal boundary conditions. We find that the lightest neutralino or sneutrino emerge as dark matter candidates, with different low scale implications. Secondly, we perform a comprehensive analysis of the secluded UMSSM model, consistent with present experimental constraints. In this model the additional $Z^\prime$ gauge boson can be leptophobic without resorting to gauge kinetic mixing and, thus lowering the LHC bounds on its mass. Thirdly, we test $E_6$ realisations of a generic $U(1)'$ extended Minimal Supersymmetric Standard Model (UMSSM) against all currently available data, from space to ground experiments, from low to high energies. Large gauge kinetic mixing implies that the $Z'$ boson emerging from the breaking of the additional $U(1)'$ symmetry is rather wide since it decays mainly into $WW$ pairs. In extensions of non-supersymmetric realisations, we study mass bounds of the $W_R$ gauge boson in generic left-right symmetric models. Assuming that the gauge bosons couple universally to quarks and leptons, we allow different gauge couplings $g_R \ne g_L$ and mass mixing, $V_{CKM}^L \ne V_{CKM}^R$ in the left and right sectors. $W_R$ mass bounds can be considerably relaxed, while $Z_R$ mass bounds are much more stringent. In addition, we perform a consistent analysis of the alternative left-right symmetric model emerging from $E_6$ grand unification. We show that the exotic neutrino inherent to this class of models, the scotino, is a viable candidate for dark matter satisfying relic density and direct detection constraints.

Download or read book Supersymmetric Dark Matter Above the W Mass written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-16 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cosmological consequences are studied for the minimal supersymmetric extension of the standard model in the case that the neutralino is heavier than W. The cross section was calculated for annihilation of heavy neutralinos into final states containing gauge and Higgs bosons (XX yields WW, ZZ, HH, HW, HZ), where X is the lightest, nth neutralino and the results are compared with the results with those previously obtained for annihilation into fermions to find the relic cosmological abundance for the most general neutralino. The new channels are particularly important for the Higgsino-like and mixed-state neutralinos, but are sub-dominant (to the fermion-antifermion annihilation channels) in the case that the neutralino is mostly a gaugino. The effect of the top quark mass is also considered. Using these cross sections and the cosmological constraint omega(sub X)h squared is less than or approximately 1, the entire range of cosmologically acceptable supersymmetric parameter space is mapped and a very general bound on the neutralino mass is discovered. For a top quark mass of less than 180 GeV, neutralinos heavier than 3200 GeV are cosmologically inconsistent, and if the top quark mass is less than 120 GeV, the bound is lowered to 2600 GeV. Neutralino states that are mostly gaugino are constrained to be lighter than 550 GeV. It is found that a heavy neutralino that contributes omega(sub X) is approximately 1 arises for a very wide range of model parameters and makes, therefore, a very natural and attractive dark matter candidate. Griest, Kim and Kamionkowski, Marc and Turner, Michael S. Unspecified Center...

Download or read book Supersymmetry and Dark Matter a New Candidate written by David Thomas and published by . This book was released on 1991 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physics Beyond the Standard Model written by David Sanford and published by . This book was released on 2012 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation we consider a number of topical issues in physics beyond the standard model. Motivated by null results from superpartner searches and the tentative Higgs boson signal at mh[subscript], [approximate] 125 GeV, we consider the framework of focus point supersymmetry. Within the focus point framework we examine models in which the neutralino is a thermal relic which saturates the observed dark matter relic density, and generalize the results for dark matter direct detection to generic models with heavy scalars. We also extend the original focus point framework to the case of non-zero A-terms, allowing models in which mh[subscript], [approximate] 125 GeV can be achieved with only 1% fine-tuning in the weak scale. We also consider formal aspects of anomaly-mediated supersymmetry breaking, in particular a recent derivation of anomaly-mediated soft masses using the full supergravity framework and its relation to the original derivation. Finally, we examine models in which recent contradictory results from light dark matter experiments can be partially explained by relaxing the common assumption of equal couplings to protons and neutrons.

Download or read book Topics in Supersymmetry and Physics Beyond the Standard Model written by Jean-François Fortin and published by . This book was released on 2009 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis we explore different aspects related to the central concepts of supersymmetry and physics beyond the Standard Model. We start by investigating fine-tuning in the minimal supersymmetric extension of the Standard Model, where the regions with the minimal amount of fine-tuning of electroweak symmetry breaking are found. Afterwards, we concentrate on a more formal aspect of supersymmetry, studying spontaneous symmetry breaking in supersymmetry using the superspace formalism. Thereafter we direct our attention to supersymmetry as physics beyond the Standard Model, looking more specifically at supersymmetry breaking in metastable states. First, we discuss possible undetected Higgs decays in the Pentagon model with renormalizable lepton number violating couplings which also explain neutrino masses. Second, we generalize metastable supersymmetry breaking in supersymmetric quantum chromodynamics to phenomenologically viable models of direct gauge mediation by adding single and multitrace deformations. Third, we introduce a new model of physics beyond the Standard Model, the Pyramid Scheme, and study its implications, focusing on dark matter and its astrophysical signatures in particular. Four, we examine tunneling constraints in models of Cosmological Supersymmetry Breaking, arguing that these models can have no supersymmetric vacuum states in the infinite Planck mass limit. Finally, we present a general study of the possible gamma ray signatures coming from dark matter annihilation or decay.

Download or read book Journeys Beyond the Standard Model written by Jessica L. Goodman and published by . This book was released on 2013 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis attempts to address two outstanding issues in the Standard Model of particle physics. The first of these two has to do with the lack of a viable dark matter candidate in the Standard Model. Many recent experimental results hint at the possibility of a light dark matter particle. If it is light enough, one may consider producing these particles at colliders. Parts of this thesis considers effective theories of dark matter as a way to develop a language to compare collider searches for dark matter to direct and indirect detection experiments. The second of these two issues explores the more aesthetic problem of the gauge hierarchy through construction of supersymmetry breaking models. In the first set of models, we construct UV completions of O'Raifeartaigh-like models which spontaneously break R symmetry. In the final chapter, we construct a R symmetric GMSB model in which we use Seiberg dynamics to generate supersoft Dirac gaugino masses.

Download or read book Supersymmetry and String Theory written by Michael Dine and published by Cambridge University Press. This book was released on 2007-01-04 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past decade has witnessed dramatic developments in the field of theoretical physics. This book is a comprehensive introduction to these recent developments. It contains a review of the Standard Model, covering non-perturbative topics, and a discussion of grand unified theories and magnetic monopoles. It introduces the basics of supersymmetry and its phenomenology, and includes dynamics, dynamical supersymmetry breaking, and electric-magnetic duality. The book then covers general relativity and the big bang theory, and the basic issues in inflationary cosmologies before discussing the spectra of known string theories and the features of their interactions. The book also includes brief introductions to technicolor, large extra dimensions, and the Randall-Sundrum theory of warped spaces. This will be of great interest to graduates and researchers in the fields of particle theory, string theory, astrophysics and cosmology. The book contains several problems, and password protected solutions will be available to lecturers at www.cambridge.org/9780521858410.