The Bestest Little Higgs

TL;DR

This paper introduces a new little Higgs model based on an SO(6)xSO(6)/SO(6) coset that addresses key issues like custodial symmetry violation and electroweak-tuning tension, with distinctive collider signatures.

Contribution

The model uniquely incorporates custodial symmetry and decouples gauge and top partner masses, improving naturalness and collider phenomenology over previous little Higgs models.

Findings

Model preserves custodial symmetry effectively.

Higgs quartic coupling is simplified and pathology-free.

Top partners are lighter, enhancing collider detectability.

Abstract

While little Higgs models provide an interesting way to address the hierarchy problem, concrete models in the literature typically face two major obstacles. First, the mechanism for generating a Higgs quartic coupling often leads to large violations of custodial symmetry. Second, there is a tension between precision electroweak observables in the gauge sector and fine-tuning in the top sector. In this work, we present a new little Higgs model which solves both of these problems. The model is based on an SO(6)xSO(6)/SO(6) coset space which has custodial symmetry built in. The Higgs quartic coupling takes a particularly simple form and does not suffer from the "dangerous singlet" pathology. We introduce a gauge breaking module which decouples the mass of gauge partners from the mass of top partners, allowing for natural electroweak symmetry breaking. The collider phenomenology is dominated by production and decay of the top partners, which are considerably lighter than in traditional little Higgs theories.