Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

The Electroweak Phase Transition in Nearly Conformal Technicolor

James M. Cline, Matti Jarvinen, Francesco Sannino

TL;DR

This work investigates the electroweak phase transition within nearly conformal technicolor, focusing on Minimal Walking Technicolor (MWT) and its low-energy composite spectrum. Using a one-loop, ring-improved effective potential, the authors map regions of parameter space where the transition is strongly first order, suitable for electroweak baryogenesis, and identify associated LHC-accessible states. They contrast heavy versus light ETC-mass scenarios to understand how the scalar sector and new fermions shape the transition, providing qualitative insight into the conditions that enhance $\phi_c/T_c$. Additionally, they discuss a potential second, confinement-driven transition at lower temperatures in theories with nontrivial center symmetry, signaling rich cosmological implications. Overall, the paper connects detailed finite-temperature dynamics of a composite Higgs system to phenomenology and cosmology in Beyond-Standard-Model contexts.

Abstract

We examine the temperature-dependent electroweak phase transition in extensions of the Standard Model in which the electroweak symmetry is spontaneously broken via strongly coupled, nearly-conformal dynamics. In particular, we focus on the low energy effective theory used to describe Minimal Walking Technicolor at the phase transition. Using the one-loop effective potential with ring improvement, we identify significant regions of parameter space which yield a sufficiently strong first order transition for electroweak baryogenesis. The composite particle spectrum corresponding to these regions can be produced and studied at the Large Hadron Collider experiment. We note the possible emergence of a second phase transition at lower temperatures. This occurs when the underlying technicolor theory possesses a nontrivial center symmetry.

The Electroweak Phase Transition in Nearly Conformal Technicolor

TL;DR

This work investigates the electroweak phase transition within nearly conformal technicolor, focusing on Minimal Walking Technicolor (MWT) and its low-energy composite spectrum. Using a one-loop, ring-improved effective potential, the authors map regions of parameter space where the transition is strongly first order, suitable for electroweak baryogenesis, and identify associated LHC-accessible states. They contrast heavy versus light ETC-mass scenarios to understand how the scalar sector and new fermions shape the transition, providing qualitative insight into the conditions that enhance . Additionally, they discuss a potential second, confinement-driven transition at lower temperatures in theories with nontrivial center symmetry, signaling rich cosmological implications. Overall, the paper connects detailed finite-temperature dynamics of a composite Higgs system to phenomenology and cosmology in Beyond-Standard-Model contexts.

Abstract

We examine the temperature-dependent electroweak phase transition in extensions of the Standard Model in which the electroweak symmetry is spontaneously broken via strongly coupled, nearly-conformal dynamics. In particular, we focus on the low energy effective theory used to describe Minimal Walking Technicolor at the phase transition. Using the one-loop effective potential with ring improvement, we identify significant regions of parameter space which yield a sufficiently strong first order transition for electroweak baryogenesis. The composite particle spectrum corresponding to these regions can be produced and studied at the Large Hadron Collider experiment. We note the possible emergence of a second phase transition at lower temperatures. This occurs when the underlying technicolor theory possesses a nontrivial center symmetry.

Paper Structure

This paper contains 19 sections, 63 equations, 3 figures.

Table of Contents

  1. Introduction
  2. Introducing Minimal Walking Technicolor
  3. The underlying degrees of freedom and Lagrangian
  4. Tree Level Low Energy Theory for MWT
  5. Scalar Sector
  6. Fourth Lepton Family and Yukawa Interactions
  7. MWT - Effective Potential
  8. Zero Temperature Contribution
  9. One Loop Finite Temperature Effective Potential
  10. Results
  11. Heavy ETC-induced masses
  12. Light ETC-induced masses
  13. Explanation of Results
  14. A novel phase transition at lower energies
  15. Zero- and Finite-Temperature Background Dependent Scalar Masses
  16. ...and 4 more sections

Figures (3)

  • Figure 1: The strength of the phase transition ($\phi_c/T_c$) in the $M_H$-$M_{\Theta}$ plane for $M_A$, $M_{\rm f}=150$ GeV and $300$ GeV, in the heavy ETC mass scenario. $\phi_c/T_c=0.5,1.0,1.5,\ldots3.0$ at the contour lines, such that $\phi_c/T_c<0.5$ in the region with lightest color. In the white region in the upper left corners of the plots the broken phase vacuum is metastable already at $T=0$.
  • Figure 2: The strength of the phase transition ($\phi_c/T_c$) in the $M_H$-$M_{\Theta}$ plane, for the light ETC mass ($m_{\rm ETC}=150$ GeV) scenario. $M_A$ and $M_{\rm f}$ are varied as indicated in the labels.
  • Figure 3: Typical shape of bosonic contribution to one-loop zero temperature potential, eqs. (\ref{['VT0']},\ref{['fdef']}), which helps to enhance the strength of the phase transition.