Electroweak scale invariant models with small cosmological constant

TL;DR

This paper explores scale invariant models broken by radiative corrections at the electroweak scale, offering solutions to the hierarchy problem and predicting new particles, with extensions compatible with current experimental data.

Contribution

It introduces minimal and extended scale invariant models that address the hierarchy problem and are consistent with LHC data, predicting a light pseudo-Goldstone boson and fermionic-bosonic mass relations.

Findings

Minimal model disfavoured by LHC data

Extensions with neutrino masses and dark matter are viable

Models predict a light pseudo-Goldstone boson around 10 GeV or less

Abstract

We consider scale invariant models where the classical scale invariance is broken perturbatively by radiative corrections at the electroweak scale. These models offer an elegant and simple solution to the hierarchy problem. If we further require the cosmological constant to be small then such models are also highly predictive. Indeed, the minimal such model, comprising a Higgs doublet and a real singlet, has the same number of parameters as the standard model. Although this minimal model is disfavoured by recent LHC data, we show that two specific extensions incorporating neutrino masses and dark matter are fully realistic. That is, consistent with all experiments and observations. These models predict a light pseudo-Goldstone boson, $h$, with mass around 10 GeV or less. A fermionic-bosonic mass relation is also predicted. The specific models considered, as well as more generic scale invariant models, can be probed at the LHC.