Two Lectures on Technicolor

TL;DR

This paper reviews technicolor theories, addressing their motivations, challenges like flavor-changing neutral currents, and proposed solutions such as walking technicolor and topcolor-assisted technicolor, along with a novel CP violation scenario.

Contribution

It provides a comprehensive overview of technicolor models, discusses their phenomenological issues, and introduces a new CP violation mechanism with rational phase structure.

Findings

Walking technicolor and topcolor help resolve flavor and electroweak issues.

A novel CP violation scenario achieves tiny phases without fine-tuning.

Constraints on quark mass matrices from meson mixing and CP parameters.

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.