Neutrino oscillations and large extra dimensions

Assuming that right-handed neutrinos exist and propagate in some large extr a dimensions, we attempt to give a comprehensive description of the phenome nology of neutrino oscillations. A few alternative explanations of the atmo spheric neutrino anomaly emerge, different from the standard nu(mu) --> nu( tau) or nu(mu) --> nu(sterile) interpretations. Constraints from nucleosynt hesis and supernova 1987a are discussed. The constraints from SN1987a indic ates a maximum radius of any extra dimension of about 1 Angstrom. (C) 2000 Elsevier Science B.V. All rights reserved.