Restoring Naturalness via Conjugate Fermions

TL;DR

This paper introduces a new mechanism in composite Higgs models that cancels leading order potential contributions, significantly reducing fine-tuning and predicting unique LHC signatures.

Contribution

It presents a novel conjugate fermion mechanism that cancels the leading order potential in composite Higgs models, lowering fine-tuning and suggesting distinctive experimental signatures.

Findings

Fine-tuning reduced to 10% at $f=1600$ GeV

Mechanism involves splitting real representations into complex conjugates

Predicts quarks with baryon number $B=2/3$ with distinctive decays

Abstract

We propose a novel mechanism for cancelling the leading order contribution to the potential in composite Higgs scenarios. The mechanism relies on the splitting of a real representation of the global symmetry into a complex representation and its conjugate of the unbroken group. We identify two cosets one of which includes a custodial symmetry. A numerical analysis is performed in a phenomenological three-site model and the resulting fine-tuning is analysed. The cancelling of the leading order potential results in a drastic reduction of the fine-tuning. For a symmetry breaking scale of the strong sector as high as $f=1600$ GeV, fine-tuning can be as good as $10\%$ or even better. We discuss a possible interpretation in the 5D holographic dual. Unique signatures of the model include quarks with baryon number $B=2/3$ with highly distinctive decays which can be looked for at the LHC.