Matter-antimatter oscillations and neutrino mass

A discussion of neutron-antineutron (n - anti-n) and hydrogen-antihydrogen (H - anti-H) transitions is presented. An SU(2)/sub L/ x U(1) x SU(3)/sub c/ model with spontaneously broken global B-L symmetry is shown to predict the interesting connection between oscillation times T/sub n - anti-n/, T/sub H - anti-H/, neutrino mass and the mass of a doubly charged Higgs scalar. A case of B-L as a gauge symmetry is discussed in the context of SU(2)/sub L/ x SU(2)/sub R/ x U(1)/sub B-L/ x SU(3)/sub c/ gauge model, with the emphasis on matter oscillations. Finally, an analysis of Higgs mass scales in GUTS and their impact on such processes is offered