Light sterile neutrinos from large extra dimensions

An experimentally verifiable Higgs-triplet model of neutrino masses from large extra dimensions was recently proposed. We extend it to accommodate a light sterile neutrino which also mixes with the three active neutrinos. Another extension without the Higgs triplet allows the specific realization of a previously proposed phenomenological model of neutrino oscillations with decay to account for the LSND data, which is now the only viable such model now left, in view of the latest atmospheric and solar neutrino-oscillation data from the Super-Kamiokande collaboration.