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Orientifold theory dynamics and symmetry breaking

Francesco Sannino, Kimmo Tuominen

TL;DR

Dynamical electroweak symmetry breaking is explored via orientifold gauge theories with fermions in two-index symmetric or antisymmetric representations, exploiting a large-$N$ mapping to supersymmetric Yang-Mills (SYM) to obtain robust nonperturbative constraints. The study demonstrates that the minimal two-flavor, S-type setup lies near the conformal window across a range of colors, while A-type theories exhibit different walking behavior with larger allowable $N_f$, all illuminated by SYM-based insights. By deriving phase diagrams and leveraging SYM correspondences, the work yields predictions for the hadronic spectrum, including light scalar channels, and implications for the electroweak $S$ parameter. These results offer a concrete, testable pathway for walking technicolor that can be probed at colliders and via lattice simulations, potentially providing a natural mechanism for electroweak symmetry breaking with a small number of techniflavors.

Abstract

We show that it is possible to construct explicit models of electroweak symmetry breaking in which the number of techniflavors needed to enter the conformal phase of the theory is small and weakly dependent on the number of technicolors. Surprisingly, the minimal model with {\it just} two (techni)flavors, together with a suitable gauge dynamics, can be made almost conformal. The theories we consider are generalizations of orientifold type gauge theories, in which the fermions are in either two index symmetric or antisymmetric representation of the gauge group, as the underlying dynamics responsible for the spontaneous breaking of the electroweak symmetry. We first study their phase diagram, and use the fact that specific sectors of these theories can be mapped into supersymmetric Yang-Mills theory to strengthen our results. This correspondence allows us also to have information on part of the nonperturbative spectrum. We propose and investigate some explicit models while briefly exploring relevant phenomenological consequences. Our theories not only can be tested at the next collider experiments but, due to their simple structure, can also be studied via current lattice simulations.

Orientifold theory dynamics and symmetry breaking

TL;DR

Dynamical electroweak symmetry breaking is explored via orientifold gauge theories with fermions in two-index symmetric or antisymmetric representations, exploiting a large- mapping to supersymmetric Yang-Mills (SYM) to obtain robust nonperturbative constraints. The study demonstrates that the minimal two-flavor, S-type setup lies near the conformal window across a range of colors, while A-type theories exhibit different walking behavior with larger allowable , all illuminated by SYM-based insights. By deriving phase diagrams and leveraging SYM correspondences, the work yields predictions for the hadronic spectrum, including light scalar channels, and implications for the electroweak parameter. These results offer a concrete, testable pathway for walking technicolor that can be probed at colliders and via lattice simulations, potentially providing a natural mechanism for electroweak symmetry breaking with a small number of techniflavors.

Abstract

We show that it is possible to construct explicit models of electroweak symmetry breaking in which the number of techniflavors needed to enter the conformal phase of the theory is small and weakly dependent on the number of technicolors. Surprisingly, the minimal model with {\it just} two (techni)flavors, together with a suitable gauge dynamics, can be made almost conformal. The theories we consider are generalizations of orientifold type gauge theories, in which the fermions are in either two index symmetric or antisymmetric representation of the gauge group, as the underlying dynamics responsible for the spontaneous breaking of the electroweak symmetry. We first study their phase diagram, and use the fact that specific sectors of these theories can be mapped into supersymmetric Yang-Mills theory to strengthen our results. This correspondence allows us also to have information on part of the nonperturbative spectrum. We propose and investigate some explicit models while briefly exploring relevant phenomenological consequences. Our theories not only can be tested at the next collider experiments but, due to their simple structure, can also be studied via current lattice simulations.

Paper Structure

This paper contains 1 section, 8 equations, 2 figures.

Table of Contents

  1. Further constraints from super Yang-Mills

Figures (2)

  • Figure 1: Phase diagram as function of number of $N_f$ dirac flavors and $N$ colors for fermions in the two-index symmetric representation (S-types) of the gauge group.
  • Figure 2: Phase diagram as function of number of $N_f$ dirac flavors and $N$ colors for fermions in the two-index antisymmetric representation (A-types) of the gauge group.