Light Sterile Neutrinos, Left-Right Symmetry, and $0\nu\beta\beta$ Decay

TL;DR

This paper explores how light right-handed neutrinos in left-right symmetric models influence neutrinoless double beta decay rates, suggesting potential detectability in future experiments and discussing implications for the strong CP problem.

Contribution

It provides a systematic analysis of $0 uetaeta$ decay contributions from light right-handed neutrinos within minimal left-right symmetric models using an effective field theory approach.

Findings

Light right-handed neutrinos can enhance $0 uetaeta$ decay rates.

Detection prospects are promising even for normal hierarchy.

Implications for the strong CP problem are discussed.

Abstract

We investigate neutrinoless double beta ($0\nu\beta\beta$) decay rates in minimal left-right symmetric models in presence of relatively light right-handed neutrinos. By use of an effective field theory approach, we systematically include all contributions in the model as well as the dependence of the decay amplitude on the masses of right-handed neutrinos. In type-I and type-II seesaw scenarios, we analyze the impact of right-handed neutrinos heavier than about 10 MeV, showing that this effect can lead to a detection of $0\nu\beta\beta$ decay in the next-generation experiments even for the normal hierarchy and a relatively large right-handed scale set by the mass of hypothetical right-handed gauge bosons. Finally, we comment on a possible connection between light right-handed neutrinos and the strong CP problem.