Download or read book Direct Gauge Mediation of Supersymmetry Breaking with a Strongly Coupled Hidden Sector written by Jeff L. Jones and published by . This book was released on 2009 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Strongly Coupled Semi Direct Mediation of Supersymmetry Breaking written by and published by . This book was released on 2011 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supersymmetry (SUSY) is expected to be a crucial ingredient of basic laws in Nature. It is an attractive possibility that SUSY is broken at low energy within the experimental reach in the near future. Among others, low-energy dynamics with gauge mediation between a hidden sector of SUSY breaking and the visible sector of SUSY standard model may be phenomenologically viable. In particular, the gauge interactions are flavor blind, so that the unwanted flavor-changing processes are naturally suppressed. Strongly coupled semi-direct gauge mediation models of supersymmetry breaking through massive mediators with standard model charges are investigated by means of composite degrees of freedom. Sizable mediation is realized to generate the standard model gaugino masses for a small mediator mass without breaking the standard model symmetries.

Download or read book Supersymmetry Breaking Models of Gauge Mediation with Gauge Messengers written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: With the start of the LHC, it becomes increasingly important to understand the experimental signatures that discriminate different extensions of the standard model. Supersymmetry (SUSY), in particular the Minimal Supersymmetric Standard Model (MSSM), is one such extension that is specially attractive by its simplicity and elegance. However, if this symmetry is to be realized in nature, it must be spontaneously broken. In this work we will try to understand the most general way in which SUSY breaking can happen in renormalizable field theories and the implications that this has on the minimal extension of the standard model (MSSM) mass spectrum. The first two chapters are the introductory material: in chapter 1 we will introduce some of the key ideas necessary to understand supersymmetric field theories, and in chapter 2 we will briefly describe the the simplest supersymmetric version of the Standard Model. In chapter 3 we will focus on understanding the role of R-Symmetry breaking in determining the soft terms gauge mediation of supersymmetry breaking (GMSB) can lead to. To do this we consider a model where both R-symmetry and SUSY are spontaneously broken. One starts with the model proposed by Intriligator, Seiberg and Shih (ISS) and adds a (dangerous) marginal operator, which we call a meson deformation. The inclusion of this operator leads to the spontaneous breaking of R-symmetry in the vacuum. One then gauges the SU(5) of flavour and identifies it with the MSSM GUT gauge group, thus implementing GMSB. This was the second explicit example where R-symmetry was spontaneously broken in the vacuum. As in the first, gaugino masses iii turned out to be smaller than naively expected so that a mild splitting between scalar (squark and slepton) and gaugino masses exists. After this, a general argument showed that in fact gaugino masses are always significantly smaller than scalar masses if the universe is perturbatively stable. This arguments suggests that any viable vac.

Download or read book Holographic Gauge Mediation written by and published by . This book was released on 2009 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: We discuss gravitational backgrounds where supersymmetry is broken at the end of a warped throat, and the SUSY-breaking is transmitted to the Standard Model via gauginos which live in (part of) the bulk of the throat geometry. We find that the leading effect arises from splittings of certain 'messenger mesons, ' which are adjoint KK-modes of the D-branes supporting the Standard Model gauge group. This picture is a gravity dual of a strongly coupled field theory where SUSY is broken in a hidden sector and transmitted to the Standard Model via a relative of semi-direct gauge mediation.

Download or read book Duality and Models of Supersymmetry Breaking written by Callum Durnford and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Duality is often most clearly manifest in supersymmetric theories, where the rigid mathematical structure affords good control over the behaviour of the system. In many real-world applications, and particularly in particle physics at the TeV scale, supersymmetry can only be present as a broken symmetry. In this thesis we explore various situations in which duality can continue be important when supersymmetry is broken spontaneously, or even explicitly. We first focus on the AdS/CFT correspondence, and consider the effect of instantons in a non-supersymmetric gauge theory obtained via a marginal deformation of N = 4 super Yang-Mills. This gauge theory is expected to be dual to type IIB string theory on a background that is the product of five-dimensional anti-de Sitter spacetime and a deformed five-sphere. By performing an instanton calculation in the deformed gauge theory we extract a prediction for the dilaton-axion field in dual string theory. In the limit of small deformations where the supergravity regime is valid, our instanton result reproduces the expression for the axio-dilaton of the supergravity solution originally found by Frolov, thus supporting the validity of the correspondence. We then go on to look at how supersymmetry breaking in a metastable vacuum allows one to build simple and concrete models of gauge mediation. In the prototypical model of Intriligator, Seiberg and Shih (ISS), Seiberg duality plays an important role in ensuring the longevity of the metastable vacuum. In a move to construct more realistic models we deform the ISS model by adding a baryon term to the superpotential. This simple deformation causes spontaneous breaking of the approximate R-symmetry of the metastable vacuum. We then gauge an SU(5) flavour group and identify it with the parent gauge symmetry of the supersymmetric Standard Model. This implements direct mediation of supersymmetry breaking without the need for an additional messenger sector. A reasonable choice of parameters leads to gaugino masses of the right order. To further explore the phenomenology of metastable susy breaking we distinguish different types of models by the manner in which R-symmetry is broken in the metastable vacuum. In general, there are two possible ways to break R-symmetry: explicitly or spontaneously. We find that the MSSM phenomenology can be greatly affected how this breaking occurs in the Hidden Sector. Explicit R-symmetry breaking models lead to fairly standard gauge mediation patterns, but we argue that in the context of ISS-type models this only makes sense if B = 0 at the mediation scale. This leads to high values of tan beta as a generic prediction. If on the other hand R-symmetry is broken spontaneously, then R-violating soft terms tend to be suppressed with respect to the R-symmetry preserving ones, and one is led to a scenario with large scalar masses. These models interpolate between standard gauge mediation and split SUSY models. We provide benchmark points for the two scenarios, which serve to demonstrate that the specific dynamics of the Hidden Sector - the underlying nature of supersymmetry and R-symmetry breaking - can considerably affect the mass spectrum of the MSSM.

Download or read book Degrees of Metastability in Gauge Mediated Supersymmetry Breaking written by James Barnard and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis consists of an investigation into supersymmetry and its breaking. Emphasis is placed on the question of metastability and the role of non-topological solitons in the hidden sector. A desirable feature in models employing direct gauge mediation is that of tree level metastability, in order to generate large enough gaugino masses. An explicit realisation of this idea is constructed via a simple deformation of SQCD that is well motivated and needs no fine tuning. Any viable metastable supersymmetry breaking vacuum must also be stable enough to survive until the present day. Non-topological solitons, or Q-balls, are supported in all such vacua where there is a conserved, global U(1) symmetry and no massless, charged scalars. It is shown that for a broad class of models Q-balls are extremely influential on the vacuum lifetime and make seemingly viable vacua catastrophically short lived. Even when there is no effect on vacuum stability flat directions charged under an R-symmetry are a ubiquitous feature of O'Raifeartaigh models. Non-topological solitons associated with this symmetry, R-balls, are likely to form through the fragmentation of a condensate. Their cosmology is studied and it is found that they can have significant observable effects, from acting as a good dark matter candidate to providing the primary source of reheating in the early universe.

Download or read book A Simple and Realistic Model of Supersymmetry Breaking written by and published by . This book was released on 2007 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a simple and realistic model of supersymmetry breaking. In addition to the minimal supersymmetric standard model, we only introduce a hidden sector gauge group SU(5) and three fields X, F and \bar{F}. Supersymmetry is broken at a local minimum of the potential, and its effects are transmitted to the supersymmetric standard model sector through both standard model gauge loops and local operators suppressed by the cutoff scale, which is taken to be the unification scale. The form of the local operators is controlled by a U(1) symmetry. The generated supersymmetry breaking and mu parameters are comparable in size, and no flavor or CP violating terms arise. The spectrum of the first two generation superparticles is that of minimal gauge mediation with the number of messengers N_mess = 5 and the messenger scale 1011 GeV

Download or read book Supersymmetry Breaking in String Theory written by and published by . This book was released on 1990 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: I briefly review the problems with previous investigations of supersymmetry breaking in string theory -- at tree-level, at one-loop, and non-perturbatively. A variant of the original non-perturbative scenario is proposed, in which gaugino condensation takes place in two different strongly-interacting hidden-sector gauge groups. In the new scenario it is possible to generate a large hierarchy of mass scale and to simultaneously stabilize the dilaton at a large expectation value (weak coupling). However, it is still uncertain whether supersymmetry is broken in such a vacuum. 26 refs.

Download or read book Improved Single Sector Supersymmetry Breaking written by and published by . This book was released on 1998 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: Building on recent work by N. Arkani-Hamed and the present authors, we construct realistic models that break supersymmetry dynamically and give rise to composite quarks and leptons, all in a single strongly-coupled sector. The most important improvement compared to earlier models is that the second-generation composite states correspond to dimension-2 ''meson'' operators in the ultraviolet. This leads to a higher scale for flavor physics, and gives a completely natural suppression of flavor-changing neutral currents. We also construct models in which the hierarchy of Yukawa couplings is explained by the dimensionality of composite states. These models provide an interesting and viable alternative to gravity- and gauge-mediated models. The generic signatures are unification of scalar masses with different quantum numbers at the compositeness scale, and lighter gaugino, Higgsino, and third-generation squark and slepton masses. We also analyze large classes of models that give rise to both compositeness and supersymmetry breaking, based on gauge theories with confining, fixed-point, or free-magnetic dynamics.

Download or read book Aspects of Supersymmetry Breaking written by John D. Mason and published by . This book was released on 2008 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Supersymmetry Breaking Gauge Mediation and the LHC written by and published by . This book was released on 2015 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gauge mediated SUSY breaking (GMSB) is a promising class of supersymmetric models that automatically satisfies the precision constraints. Prior work of Meade, Seiberg and Shih in 2008 established the full, model-independent parameter space of GMSB, which they called "General Gauge Mediation" (GGM). During the first half of 2010-2015, Shih and his collaborators thoroughly explored the parameter space of GGM and established many well-motivated benchmark models for use by the experimentalists at the LHC. Through their work, the current constraints on GGM from LEP, the Tevatron and the LHC were fully elucidated, together with the possible collider signatures of GMSB at the LHC. This ensured that the full discovery potential for GGM could be completely realized at the LHC.

Download or read book Supersymmetry Breaking and Its Mediation in String Theory and Particle Physics written by Matthew A. Buican and published by . This book was released on 2009 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Introduction To Supersymmetry 2nd Edition written by Muller-kirsten Harald J W and published by World Scientific Publishing Company. This book was released on 2010-01-21 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supersymmetry is a symmetry which combines bosons and fermions in the same multiplet of a larger group which unites the transformations of this symmetry with that of spacetime. Thus every bosonic particle must have a fermionic partner and vice versa. Since this is not what is observed, this symmetry with inherent theoretical advantages must be badly broken. It is hoped that the envisaged collider experiments at CERN will permit a first experimental test, which is expected to revive the interest in supersymmetry considerably.This revised edition of the highly successful text of 20 years ago provides an introduction to supersymmetry, and thus begins with a substantial chapter on spacetime symmetries and spinors. Following this, graded algebras are introduced, and thereafter the supersymmetric extension of the spacetime Poincaré algebra and its representations. The Wess-Zumino model, superfields, supersymmetric Lagrangians, and supersymmetric gauge theories are treated in detail in subsequent chapters. Finally the breaking of supersymmetry is addressed meticulously. All calculations are presented in detail so that the reader can follow every step.

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 Theories with Gauge mediated Supersymmetry Breaking written by G. F. Giudice and published by . This book was released on 1999 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Direct Mediation of Meta Stable Supersymmetry Breaking written by Hirosi Ooguri and published by . This book was released on 2006 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The supersymmetric SU(N{sub c}) Yang-Mills theory coupled to NF matter fields in the fundamental representation has meta-stable vacua with broken supersymmetry when N{sub C}

Download or read book Supersymmetry Breaking in Superstring Theory by Gaugino Condensation and Its Phenomenology written by and published by . This book was released on 1997 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Weakly-coupled heterotic string is known to have problems of dilaton/moduli stabilization, supersymmetry breaking (by hidden-sector gaugino condensation), gauge coupling unification, QCD axion, as well as cosmological problems involving dilaton/moduli and axion. The author studies these problems by adopting the point of view that they arise mostly due to limited calculational power, little knowledge of the full vacuum structure, and an inappropriate treatment of gaugino condensation. It turns out that these problems can be solved or are much less severe after a more consistent and complete treatment. There are two kinds of non-perturbative effects in the construction of string effective field theory: the field-theoretical non-perturbative effects of gaugino condensation (with an important constraint ignored in the past) and the stringy nonperturbative effects conjectured by S. Shenker, which are best described using the linear multiplet formalism. Stringy non-perturbative corrections to the Kaehler potential are invoked to stabilize the dilaton at a value compatible with a weak coupling regime. Modular invariance is ensured through the Green-Schwarz counterterm and string threshold corrections which, together with hidden matter condensation, lead to moduli stabilization at the self-dual point where the vev's of moduli's F components vanish. In the vacuum, supersymmetry is broken at a realistic scale with vanishing cosmological constant. As for soft supersymmetry breaking, this model always leads to a dilaton-dominated scenario. For the strong CP problem, the model-independent axion has the right properties to be the QCD axion. Furthermore, there is a natural hierarchy between the dilaton/moduli mass and the gravitino mass, which could solve both the cosmological moduli problem and the cosmological problem of the model-independent axion.