Aspects Of Electroweak Symmetry Breaking In Physics Beyond The Standard Model

Fine tuning in the Standard Model (SM) is the basis for a widespread expectation that the minimal model for electroweak symmetry breaking, with a single Higgs boson, is not realised in nature and that new physics, in addition to (or instead of) the Higgs, will be discovered at the Large Hadron Collider (LHC). However constraints on new physics indicate that many models which go beyond the SM (BSM) may also be fine tuned (although to a much lesser extent). To test this a reliable, quantitative measure of tuning is required. We review the measures of tuning used in the literature and propose an alternative measure. We apply this measure to several toy models and a constrained version of the Minimal Supersymmetric Standard Model. The Exceptional Supersymmetric Standard Model (E6SSM) is another BSM motivated by naturalness. As a supersymmetric theory it solves the SM hierarchy problem and by breaking a new gauged U(1) symmetry it also solves the Âμ-problem of the MSSM. We investigate the Renormalisation Group Evolution of the model and test for radiative electroweak symmetry breaking in two versions of the model with different high scale constraints. First we briefly look at scenarios with non-universal Higgs masses at the GUT scale and present a particle spectrum that could be observed at the LHC. Secondly we study the constrained E6SSM (CE6SSM), with universal scalar (m0), trilinear (A0) and gaugino (M) masses. We reveal a large volume of CE6SSM parameter space where the correct breakdown of the gauge symmetry can be achieved and all experimental constraints can be satisfied. We present benchmark points corresponding to different patterns of the particle spectrum. A general feature of the benchmark spectra is a light sector of SUSY particles consisting of a light gluino, two light neutralinos and a light chargino. Although the squarks, sleptons and Z boson are typically much heavier, the exotic color triplet charge 1/3 fermions as well as the lightest stop can be also relatively light leading to spectacular new physics signals at the LHC.

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.

With this thesis the author contributes to the development of a non-mainstream but long-standing approach to electroweak symmetry breaking based on an analogy with superconductivity. Electroweak symmetry breaking is assumed to be caused by dynamically generated masses of typical fermions, i.e., of quarks and leptons, which in turn assumes a new dynamics between quarks and leptons. Primarily it is designed to generate fermion masses and electroweak symmetry breaking is an automatic consequence. After the summary of the topic, the first main part of the thesis addresses the question as to whether the masses of known quarks and leptons provide sufficiently strong sources of electroweak symmetry breaking. It is demonstrated that neutrino masses subject to the seesaw mechanism are indispensable ingredients. The other two parts of the thesis are dedicated to the presentation of two particular models: The first model is based on the new strong Yukawa dynamics and serves as a platform for studying the ability to reproduce fermion masses. The second, more realistic model introduces a flavor gauge dynamics and its phenomenological consequences are studied. Even though, in the past, this type of models has already been of some interest, following the discovery of the Standard-Model-like Higgs particle, it is regaining its relevance.

This new edition of The Standard Model and Beyond presents an advanced introduction to the physics and formalism of the standard model and other non-abelian gauge theories. It provides a solid background for understanding supersymmetry, string theory, extra dimensions, dynamical symmetry breaking, and cosmology. In addition to updating all of the experimental and phenomenological results from the first edition, it contains a new chapter on collider physics; expanded discussions of Higgs, neutrino, and dark matter physics; and many new problems. The book first reviews calculational techniques in field theory and the status of quantum electrodynamics. It then focuses on global and local symmetries and the construction of non-abelian gauge theories. The structure and tests of quantum chromodynamics, collider physics, the electroweak interactions and theory, and the physics of neutrino mass and mixing are thoroughly explored. The final chapter discusses the motivations for extending the standard model and examines supersymmetry, extended gauge groups, and grand unification. Thoroughly covering gauge field theories, symmetries, and topics beyond the standard model, this text equips readers with the tools to understand the structure and phenomenological consequences of the standard model, to construct extensions, and to perform calculations at tree level. It establishes the necessary background for readers to carry out more advanced research in particle physics. Supplementary materials are provided on the author’s website and a solutions manual is available for qualifying instructors.

Symmetry and its various realizations have played a pivotal role in the development of the extremely well tested Standard Model of the strong, weak and electromagnetic interactions. In this Element, the author traces the development of the model through the interplay of the different symmetries realized in the various components of the model as well as in other sub-fields of physics.

An introduction to symmetry breaking in the standard model / Edward Farhi -- Physics beyond the standard model / Jonathan A. Bagger -- Chiral effective Lagrangians / Heinrich Leutwyler -- Towards semi-classical string theory / Jeffrey A. Harvey -- Renormalization of electroweak gauge interactions / Dallas C. Kennedy -- Electroweak experiments at LEP / Alain Blondel -- The CKM matrix and CP violation / Yosef Nir -- Axion searches / Pierre Sikivie -- Lattice QCD / Andreas S. Kronfeld -- Introduction to perturbative QCD / George Sterman -- Heavy quark effective field theory / Howard Georgi -- Heavy flavor physics on the lattice / Estia Eichten -- Two lectures on neutrinos / Pierre Ramond

Contents:Critical Current Density of High-Temperature Superconductors (P Chu)Electroweak Symmetry-Breaking Effects at Colliders (V Barger)Precision Tests of the Electroweak Theory (R D Peccei)Hadron Colliders: B Factories for Now and the Future (N S Lockyer)The MSW Effect as the Solution to the Solar Neutrino Problem (S P Rosen)New Physics Effects from String Models (R Arnowitt & P Nath)Solar Neutrino Puzzle and Physics Beyond the Standard Model (R N Mohapatra)The SFT: A Super Fixed Target Beauty Facility at the SSC (B Cox)Non-Standard Stellar Evolution (V Trimble)Analogous Behaviour in the Quantum Hall Effect, Anyon Superconductivity, and the Standard Model (R B Laughlin & S B Libby)Gauge Boson Dynamics (C Quigg)Interpreting Precision Measurements (G L Kane)Rare K Decays: Present Status and Future Prospects (S G Wojcicki)Quantum Mechanics at the Black Hole Horizon (G't Hooft)Target-Space Duality and the Curse of the Wormhole (J H Schwarz)Mass Enhancement and Critical Behavior in Technicolor Theories (T Appelquist)Proton-Proton and Proton-Antiproton Elastic Scattering at High Energies — Theory, Phenomenology, and Experiment (T T Wu) Readership: Graduate students and high energy physicists. keywords:

This book provides a unified description of elementary particle interactions and the underlying theories, namely the Standard Model and beyond. The authors have aimed at a concise presentation but have taken care that all the basic concepts are clearly described. Written primarily for graduate students in theoretical and experimental particle physics, The Physics of the Standard Model and Beyond conveys the excitement of particle physics, centering upon experimental observations (new and old) and a variety of ideas for their interpretation. Contents: Weak Interaction; Symmetries and the Gauge Theories; The Standard Model of Electroweak Interactions; Quantum Chromodynamics; Neutrino Masses and Neutrino Oscillations; Supersymmetry; Precision Test of Electroweak Radiative Corrections and New Physics; Flavor Physics and CP Violation; Appendices: Notation and Useful Relations; Cross Sections and Feynman Rule; Basics of the Group Theory; C, P and T Transformation; The Quark Model. Readership: Graduate students, experimentalists and theorists in high energy physics.

These proceedings contain over 100 talks on all aspects of Physics Beyond the Standard Model of the strong and electroweak interactions — ranging from Supersymmetry, Grand Unification, Technicolor, Exotic Particles, and CP Violation to Baryogenesis, Dark Matter, Strings and Black Holes — by leading authorities and the most active researchers in High Energy Physics. The goal of the conference is to provide a completely current summary of the most exciting and aesthetically appealing theoretical ideas, especially with regard to their predictions for yet undiscovered new particles, interactions and consequent phenomena. Particular emphasis is placed on current experimental limits and constraints on new physics, and on expectations and predictions regarding our ability to probe and discriminate between the many possibilities through experiments at present and future colliders in the decade(s) to come.