Bi-maximal neutrino mixing in the MSSM with a single right-handed neutrino

Abstract

We discuss neutrino masses in the framework of a minimal extension of the minimal supersymmetric standard model (MSSM) consisting of an additional single right-handed neutrino superfield N with a heavy Majorana mass M, which induces a single light see-saw mass m ν 3 leaving two neutrinos massless at tree-level. This trivial extension to the MSSM may account for the atomospheric neutrino data via ν μ → ν τ oscillations by assuming a near maximal mixing angle θ 23∼ π/4 and taking Δm 23 2∼m ν 3 2∼2.5×10 −3 eV 2 . In order to account for the solar neutrino data we appeal to one-loop radiative corrections involving internal loops of SUSY particles, which we show can naturally generate an additional light neutrino mass m ν 2 ∼10 −5 eV again with near maximal mixing angle θ 12∼ π/4. The resulting scheme corresponds to so-called “bi-maximal” neutrino mixing involving “just-so” solar oscillations. We predict that the decay τ→ eγ should be observed in the near future.