Progress on symmetry breaking and generational mixing in topcolor-assisted technicolor

Topcolor-assisted technicolor provides a dynamical explanation for electroweak and flavor symmetry breaking and for the large mass of the top quark without unnatural fine tuning. I briefly review the basics of topcolor-assisted technicolor, including major constraints and a general approach to satisfying them. The main challenge to topcolor-assisted technicolor is to generate the observed mixing between heavy and light generations while breaking the strong topcolor interactions near 1 TeV. I argue that these phenomena, as well as electroweak symmetry breaking, are intimately connected and I present a scenario for them based on nontrivial patterns of technifermion condensation. I also exhibit a class of models realizing this scenario.First author draf

Technihadron production and decay in low-scale technicolor

We discuss the production and decay rates of the lightest colorsinglet technihadrons, spin-one ρT and ωT and spin-zero πT , in a minimal “straw-man” model of low-scale techicolor. The revised ρT and ωT decay rates affect the technicolor searches planned for Run II of the Tevatron Collider.Accepted manuscrip

A Case Study in Dimensional Deconstruction

We test Arkani-Hamed et al.'s dimensional deconstruction on a model that is predicted to have a naturally light composite Higgs boson, i.e., one whose mass M is much less than its binding scale \Lambda, and whose quartic coupling \lambda is large, so that its vacuum expectation value v \sim M/\sqrt{\lambda} << \Lambda also. We consider two different underlying dynamics--UV completions--at the scale \Lambda for this model. We find that the expectation from dimensional deconstruction is not realized and that low energy details depend crucially on the UV completion. In one case, M << \Lambda and \lambda << 1, hence, v \sim \Lambda. In the other, \lambda can be large or small, but then so is M, and v is still O(\Lambda).Comment: 20 pages, LaTeX, with 8 postscript figure

A Composite Higgs Model with Minimal Fine-Tuning I.~The Large-N and Weak-technicolor Limit

We suggest a criterion to minimize the amount of fine-tuning in a composite Higgs model. The paradigm of this type of model is the top-condensate model of Bardeen, Hill and Lindner (BHL). Although "minimally fine-tuned", this model failed to account correctly for the masses of the top quark and the 125~GeV Higgs boson. We propose a generalization of the BHL model that employs finely-tuned extended technicolor (ETC) plus technicolor (TC) interactions. The additional freedom of this model may accommodate both m_t(173) and M_H(125). This paper studies the large-N_{TC} and N_C limit of this model in which technicolor is weak and does not contribute to electroweak symmetry breaking. Refinements including walking-TC dynamics and a renormalization group analysis of m_t and M_H will appear in a subsequent paper. A likely generic signal of this model is enhanced production of dibosons (W^+W^- and W^\pm Z^0) and tribosons (W^+W^- Z^0) via rho_T^{0,\pm} and omega_T decay.Comment: 21 pages. Version to be published in Physical Review D (modulo a few PRD style diktats); paragraph on S-parameter and its status in walking technicolor models added to Sec. 4 at referee's request; typos fixed in Appendix equations; reference adde

Top-production and flavor physics--the talk

Because of the top quark's very large mass, about 175~GeV, it now provides the best window into flavor physics. Thus, pair--production of top quarks at the Tevatron Collider is the most incisive probe of this physics until the Large Hadron Collider turns on in the next century. In this talk I discuss how moments of the t ̄t invariant mass distribution can be used to distinguish among standard and alternative mechanisms of t ̄t production.First author draf

Progress on Symmetry Breaking and Generational Mixing in Topcolor-Assisted Technicolor

Topcolor-assisted technicolor provides a dynamical explanation for electroweak and flavor symmetry breaking and for the large mass of the top quark without unnatural fine tuning. I briefly review the basics of topcolor-assisted technicolor, including major constraints and a general approach to satisfying them. The main challenge to topcolor-assisted technicolor is to generate the observed mixing between heavy and light generations while breaking the strong topcolor interactions near 1 TeV. I argue that these phenomena, as well as electroweak symmetry breaking, are intimately connected and I present a scenario for them based on nontrivial patterns of technifermion condensation. I also exhibit a class of models realizing this scenario.Comment: 16 pages; LaTeX using sprocl.sty macro. Written version of invited talk presented at the 1996 Workshop on Strongly Coupled Gauge Theories, Nagoya, Japan, (November 1996

Non-Supersymmetric Extensions of the Standard Model

The motivations for studying dynamical scenarios of electroweak and flavor symmetry breaking are reviewed and the latest ideas, especially topcolor-assisted technicolor, are summarized. Several technicolor signatures at the Tevatron and Large Hadron Collider are described and it is emphasized that all of them are well within the reach of these colliders. (This is the written version of a plenary talk of this title at the 28th International Conference on High Energy Physics, Warsaw (1996).)Comment: 11 pages including 3 figures; LaTeX using stwol.st

Kzero--Anti-Kzero and Bzero--Anti-Bzero Constraints On Technicolor

I propose a resolution of the strong CP problem of quarks based on vacuum alignment in theories of dynamically broken electroweak and flavor symmetries. Mixing in the neutral B and K--meson systems is used to restrict the form of quark mass and mixing matrices and to constrain the masses of the topcolor gauge bosons V_8 and Z' to be greater than 5 TeV. The K^0 mixing parameter epsilon is calculated for models whose quark mass matrix leads to weak, but not strong, CP violation. It is easy to accomodate its value in some models while, in others, no reasonable combination of extended technicolor and topcolor masses can account for epsilon.Comment: 22 Pages, Latex with one postscript figure and style files. Invited talk at Les Rencontres de Physique de la Vallee d'Aoste, La Thuile, Italy, March 4-10, 200

Technicolor Signatures---Ieri, Oggi e Domani

We briefly review the basic structure of modern--day technicolor theories. We then discuss the signatures for technicolor as they were in its early days, the searches that have been recently performed at the Tevatron and LEP colliders, and the prospects for testing technicolor in Tevatron Run II and at the LHC.Comment: 35 pages, 24 figures, Latex; uses lathuile.sty;Invited talk at ``Les Rencontres de Physique de la Vallee d'Aoste'', La Thuile (Italy), 27 February--4 March 2000; minor corrections mad

New Model-Independent Limit on Muon Substructure

If the discrepancy between the theoretical and newly measured values of the muon's anomalous magnetic moment is ascribed to muon substructure, there results an improved model--independent limit on its energy scale, 1.2 TeV < Lambda_mu < 3.2 TeV at 95% C.L.Comment: 3 pages, Latex. Revised version places 95% C.L. limits on muon substructure scale. Abstract is modified to reflect this chang