Lepton number violation in top quark and neutral B meson decays

TL;DR

This paper investigates how Majorana neutrinos could cause lepton number violating decays in top quarks and B mesons, with potential observable effects at future experiments.

Contribution

It introduces a resonant mechanism for Majorana neutrinos enhancing |L|=2 decays in top quark and B meson processes, providing new predictions for branching ratios.

Findings

Branching ratios could reach 10^{-6} for certain decays.

Future experiments can test these LNV decay predictions.

Constraints on Majorana neutrino properties can be improved.

Abstract

Lepton number violation (LNV) can be induced by Majorana neutrinos in four-body decays of the neutral B meson and the top quark. We study the effects of Majorana neutrinos in these |\Delta L|=2 decays in an scenario where a single heavy neutrino can enhance the amplitude via the resonant mechanism. Using current bounds on heavy neutrino mixings, the most optimistic branching ratios turn out to be at the level of 10^{-6} for \bar{B} -> D^+e^-e^-\pi^+ and t -> bl^+l^+W^- decays. Searches for these LNV decays at future facilities can provide complementary constraints on masses and mixings of Majorana neutrinos.