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Two Lectures on Technicolor

Kenneth Lane

Abstract

These two lectures on technicolor and extended technicolor (ETC) were presented at l'Ecole de GIF at LAPP, Annecy-le-Vieux, France, in September 2001. In Lecture I, the motivation and structure of this theory of dynamical breaking of electroweak and flavor symmetries is summarized. The main phenomenological obstacles to this picture--flavor-changing neutral currents, precision electroweak measurements, and the large top-quark mass--are reviewed. Then, their proposed resolutions--walking technicolor and topcolor-assisted technicolor are discussed. In Lecture II, a scenario for CP violation is presented based on vacuum alignment for technifermions and quarks. It has the novel feature of CP--violating phases that are rational multiples of pi to better than one part in 10^{10} without fine-tuning of parameters. The scheme thereby avoids light axions and a massless up quark. The mixing of neutral mesons, the mechanism of top--quark mass generation, and the CP--violating parameters epsilon and sin(2 beta) strongly constrain the form of ETC--generated quark mass matrices.

Two Lectures on Technicolor

Abstract

These two lectures on technicolor and extended technicolor (ETC) were presented at l'Ecole de GIF at LAPP, Annecy-le-Vieux, France, in September 2001. In Lecture I, the motivation and structure of this theory of dynamical breaking of electroweak and flavor symmetries is summarized. The main phenomenological obstacles to this picture--flavor-changing neutral currents, precision electroweak measurements, and the large top-quark mass--are reviewed. Then, their proposed resolutions--walking technicolor and topcolor-assisted technicolor are discussed. In Lecture II, a scenario for CP violation is presented based on vacuum alignment for technifermions and quarks. It has the novel feature of CP--violating phases that are rational multiples of pi to better than one part in 10^{10} without fine-tuning of parameters. The scheme thereby avoids light axions and a massless up quark. The mixing of neutral mesons, the mechanism of top--quark mass generation, and the CP--violating parameters epsilon and sin(2 beta) strongly constrain the form of ETC--generated quark mass matrices.
Paper Structure (23 sections, 103 equations, 2 figures, 1 table)

This paper contains 23 sections, 103 equations, 2 figures, 1 table.

Table of Contents

  1. I. INTRODUCTION TO TECHNICOLORThis lecture closely follows my lectures at the Frascati 2000 Spring School frascati. For other recent reviews, see Refs. rscreviewcthehs.
  2. I.1 The Motivation for Technicolor and Extended Technicolor
  3. I.2 Dynamical Basics
  4. I.3 Dynamical Perils
  5. I.4 Dynamical Rescues
  6. I.5 Open Problems
  7. II. CP VIOLATION IN TECHNICOLORThis lecture is an updated version of my talks at PASCOS 2001 and La Thuile 2001 conferences pascoslathuile.
  8. II.1 Outline
  9. II.2 Introduction to Vacuum AlignmentMuch of this section is a modernized version of the discussion in Roger Dashen's classic 1971 paper rfd. All particle physicists should read that paper!
  10. II.3 The Strong CP Problem
  11. II.4 Vacuum Alignment in the Technifermion Sector
  12. II.5 A Dynamical Solution to the Strong--CP Problem
  13. II.6 Quark Mass and Mixing Matrices in ETC/TC2
  14. II.7 ETC and TC2 Four--Fermion Interactions
  15. II.8 Contributions to Weak CP Violation
  16. ...and 3 more sections

Figures (2)

  • Figure 1: Graphs for ETC generation of masses for (a) quarks and leptons and (b) technipions. The dashed line is a massive ETC gauge boson. Higher--order technicolor gluon exchanges are not indicated; from Ref. etceekl.
  • Figure 2: Extended technicolor scale $M_{ETC}/g_{ETC}$ as a function of quark mass $m_q$ renormalized at $M_{ETC}$ for $\kappa = 1$ (solid curve), $\sqrt{10}$ (dashed), and $10$ (solid); see the Appendix for details.