Correlating $0\nu\beta\beta$ decays and flavor observables in leptoquark models

TL;DR

This paper explores how minimal scalar leptoquark models that generate neutrino Majorana masses at one-loop can influence neutrinoless double-beta decay and flavor observables, revealing potential correlations and experimental signatures.

Contribution

It demonstrates that leptoquark models can produce sizable effects on $0 uetaeta$ decay rates and flavor processes, linking neutrino mass generation to observable low-energy phenomena.

Findings

Leptoquark contributions can significantly alter $0 uetaeta$ half-life predictions.

Flavor observables like kaon decays and $oldsymbol{ extmu o e}$ conversion are correlated with $0 uetaeta$ signals.

Effects remain sizable for leptoquark masses up to $oldsymbol{ ext{O}(300~ ext{TeV})}$.

Abstract

In this paper, we investigate minimal scalar leptoquark models that dynamically generate neutrino Majorana masses at the one-loop level and examine their implications for low-energy processes. We show that these models can produce viable neutrino masses, consistent with neutrino oscillation and cosmological data. By using leptoquark couplings fixed by neutrino data, we predict additional contributions to neutrinoless double-beta decays ($0\nu\beta\beta$), which are chirality enhanced and compete with the standard contributions from the Majorana masses. Our analysis demonstrates that these effects are sizable for leptoquark masses as large as $\mathcal{O}(300~\mathrm{TeV})$, potentially increasing or decreasing the $0\nu\beta\beta$ half-life, and creating an ambiguity between the normal and inverted mass ordering scenarios. Furthermore, we explore the correlation between $0\nu\beta\beta$ and flavor observables, such as kaon decays and $\mu\to e$ conversion in nuclei, emphasizing that the latter is complementary to $0\nu\beta\beta$ decays.