Constraining Walking and Custodial Technicolor

TL;DR

This paper investigates how to constrain the particle spectrum of walking technicolor models using precision measurements and modified sum rules, and explores the implications of custodial symmetry on these models' particle masses.

Contribution

It introduces constraints on walking technicolor models' spectra and analyzes the incompatibility of custodial symmetry with walking dynamics, proposing possible light axial vectors.

Findings

Walking technicolor models can be constrained via precision measurements.

Custodial technicolor models cannot originate from walking dynamics.

A very light axial vector boson is possible in certain models.

Abstract

We show how to constrain the physical spectrum of walking technicolor models via precision measurements and modified Weinberg sum rules. We also study models possessing a custodial symmetry for the S parameter at the effective Lagrangian level - custodial technicolor - and argue that these models cannot emerge from walking type dynamics. We suggest that it is possible to have a very light spin-one axial vector boson. However, in the walking dynamics the associated vector boson is heavy while it is degenerate with the axial in custodial technicolor.