A Possible Quantum-Gravitational Origin of the Neutrino Mass Difference ?

We discuss the theoretical possibility that the neutrino mass differences have part of their origin in the quantum-decoherence-inducing medium of space-time foam, which characterises some models of quantum gravity, in much the same way as the celebrated MSW effect, responsible for the contribution to mass differences when neutrinos pass through ordinary material media. We briefly describe consequences of such decoherent media in inducing CPT violation at a fundamental level, which would affect the neutrino oscillation probability; we speculate on the connection of such phenomena with the role of neutrinos for providing one possible source of a cosmological constant in the Universe, of the phenomenologically right order of magnitude. Finally we discuss possible experimental constraints on the amount of neutrino mass differences induced by quantum gravity, which are based on fits of a simple decoherence model with all the currently available neutrino data.