Majorana neutrinos with effective interactions in B decays

Abstract

Abstract We investigate the possible contribution of Majorana neutrinos to B meson decays in an effective interaction formalism, in the mass range 0.5 GeV $$<m_N<5 $$ <mN<5 GeV. We study the decay of the $$B^-$$ B- meson via $$B^- \rightarrow \mu ^- \mu ^- \pi ^+$$ B-→μ-μ-π+ at LHCb, which is a signal for leptonic number violation and the presence of Majorana neutrinos, and put bounds on different new physics contributions, characterized by their Dirac–Lorentz structure. We also study the bounds imposed by the radiative B decay ($$B^- \rightarrow \mu ^- \nu \gamma $$ B-→μ-νγ ) results from Belle. The obtained bounds are more restrictive than previous values found for dimension 6 four-fermion contact vectorial and scalar Majorana neutrino interactions in the context of the left–right symmetric model for higher Majorana masses at the LHC, showing that the direct calculation of the effective N interactions contribution to different processes can help to put more stringent bounds to different UV-complete models parameterized by an effective Lagrangian.