Quasi Goldstone fermion as a sterile neutrino

Abstract

The existence of sterile neutrinos is hinted by the simultaneous presence of diverse neutrino anomalies. We suggest that the quasi Goldstone fermions (QGF's) arising in supersymmetric theory as a result of spontaneous breaking of global symmetry such as the Peccei-Quinn symmetry or the lepton number symmetry can play the role of the sterile neutrino. The smallness of the mass of QGF's (m_S˜10^-3-10 eV) can be related to the specific choice of superpotential or Kähler potential (e.g., no-scale kinetic terms for certain superfields). Mixing of QGF's with neutrinos implies R-parity violation. It can proceed via the coupling of QGF's with Higgs supermultiplets or directly with a lepton doublet. A model which accounts for the solar and atmospheric anomalies and dark matter is presented.