Majorana neutrinos with effective interactions in B decays

Abstract

We investigate the possible contribution of Majorana neutrinos to Bmeson decays in an effective interactionformalism, in the mass range 0.5GeV<mN<5GeV.We study the decay of the B meson via B−→μ−μ−π+at LHCb, which is a signal for leptonic number violationand the presence of Majorana neutrinos, and put bounds ondifferent new physics contributions, characterized by their Dirac- Lorentz structure. We also study the bounds imposedby the radiative B decay (B−→μ−νγ) results from Belle.The obtained bounds are more restrictive than previous values found for dimension 6 four-fermion contact vectorial andscalar 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 toput more stringent bounds to different UV-complete modelsparameterized by an effective Lagrangian.