Lepton number violation by heavy Majorana neutrino in $B$ decays

Abstract

Heavy Majorana neutrinos are predicted in addition to ordinary active neutrinos in the models with the seesaw mechanism. We investigate the lepton number violation (LNV) in $B$ decays induced by such a heavy neutrino $N$ with GeV-scale mass. Especially, we consider the decay channel $B^{+}\to {\mu }^{+}N\to {\mu }^{+}{\mu }^{+}{\pi }^{-}$ and derive the sensitivity limits on the mixing angle ${\Theta }_{\mu }$ by the future search experiments at Belle II and in $e^{+}{e}^{-}$ collisions at the Future Circular Collider (FCC-ee).

Comments: 11 pages, 2 figures (Figure 2 is revised), v2: version to appear in Physics Letters B