A New Approach to Flavor Symmetry and an Extended Naturalness Principle

TL;DR

This paper proposes non-supersymmetric Standard Model extensions with multiple light scalar doublets governed by a family symmetry, using anthropic tuning to address naturalness and constrain flavor-changing processes.

Contribution

It introduces a novel class of models with extended flavor symmetry and anthropic tuning, providing new insights into naturalness and flavor constraints in particle physics.

Findings

Family symmetry constrains FCNC and proton decay operators.

Anthropic tuning makes the Standard Model Higgs and other scalars light.

Models demonstrate how extended naturalness principles inform model-building.

Abstract

A class of non-supersymmetric extensions of the Standard Model is proposed in which there is a multiplicity of light scalar doublets in a multiplet of a non-abelian family group with the Standard Model Higgs doublet. Anthropic tuning makes the latter light, and consequently the other scalar doublets remain light because of the family symmetry. The family symmetry greatly constrains the pattern of FCNC and proton decay operators coming from scalar-exchange. Such models show that useful constraints on model-building can come from an extended naturalness principle when the electroweak scale is anthropically tuned.