Neutrinos, Dark Matter and Higgs Vacua in Parity Solutions of the strong CP problem

TL;DR

This paper explores parity-based solutions to the strong CP problem, examining their implications for dark matter, neutrino physics, and collider experiments, with a focus on mirror worlds and Higgs potential stability.

Contribution

It extends models of parity solutions to the strong CP problem, analyzing dark matter candidates, cosmological implications, and collider phenomenology within mirror world frameworks.

Findings

Mirror electrons as dark matter candidates with 500-1000 GeV mass

Predictions of deviations from cold dark matter and $ ext{Δ}N_{ m eff}$

Potential collider signatures of TeV-scale colored states

Abstract

The strong CP problem can be solved if the laws of nature are invariant under a space-time parity exchanging the Standard Model with its mirror copy. We review and extend different realizations of this idea with the aim of discussing Dark Matter, neutrino physics, leptogenesis and collider physics within the same context. In the minimal realization of Ref. [1] the mirror world contains a massless dark photon, which leads to a rather interesting cosmology. Mirror electrons reproduce the dark matter abundance for masses between 500-1000 GeV with traces of strongly interacting dark matter. This scenario also predicts deviations from cold dark matter, sizable $\Delta N_{\rm eff}$ and colored states in the TeV range that will be tested in a variety of upcoming experiments. We also explore scenarios where the mirror photon is massive and the mirror particles are charged under ordinary electro-magnetism with very different phenomenology. We also show that, for the measured values of the SM parameters, the Higgs effective potential can give rise to a second minimum at large field value as required to break spontaneously the parity symmetry.