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arXiv · 2112.02227

$\Delta$L=2 hyperon decays induced by Majorana neutrinos and doubly-charged scalars

G. Hernández-Tomé·G. López Castro·D. Portillo-Sánchez
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Abstract

Searches for $\Delta L=2$ decays are crucial to disentangle the Dirac vs Majorana nature of neutrinos. While neutrinoless nuclear double beta decays are the most promising tool to look for di-electron signals of $\Delta L=2$, searches of di-lepton channels with other flavors are far less limited by statistics. We revisit the calculation of $\Delta L=2$ decays of hyperons $B^-_i\to B^+_f\ell^-\ell'^-$. We compute the rates of these decays by including the hyperon form factors, which yields finite results in the one-loop model mechanism involving Majorana neutrinos (long-range contributions). In addition, we study the short-range contributions to these kinds of processes in two appealing scenarios. First, we consider the effects of heavy Majorana neutrinos in low-scale seesaw models that involve a minimal parametrization with only two heavy Majorana states. Second, we study an alternative model where $\Delta L=2$ decays are induced by a scalar boson coupled to di-leptons to provide additional predictions.

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G. Hernández-Tomé, G. López Castro, D. Portillo-Sánchez. 2021-12-04. $\Delta$L=2 hyperon decays induced by Majorana neutrinos and doubly-charged scalars. https://doi.org/10.1103/physrevd.105.113001

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