Seesaw energy scale and the LSND anomaly -: art. no. 033005

The most general, renormalizable Lagrangian that includes massive neutrinos contains right-handed neutrino Majorana masses of order M. While there are prejudices in favor of M > M-weak, virtually nothing is known about the magnitude of M. I argue that the Liquid Scintillator Neutrino Detector (LSND) anomaly provides, currently, the only experimental hint: M similar to 1 eV. If this is the case, the LSND mixing angles are functions of the active neutrino masses and mixing and, remarkably, adequate fits to all data can be naturally obtained. I also discuss consequences of this eV-seesaw for supernova neutrino oscillations, tritium beta-decay, neutrinoless double-beta-decay, and cosmology.