Neutrino mass induced n–n‾ oscillation

The Georgi-Glashow model is the simplest possible attempt at grand unification. However, due to its particle content, the model preserves a global U ( 1 ) B − L symmetry, where B and L are baryon and lepton numbers, respectively. It thus leaves neutrinos massless just as the Standard Model does. The extensions of the Georgi-Glashow model that break lepton number by two units, i.e., scenarios with | Δ L | = 2 operator(s), naturally generate potentially viable Majorana neutrino masses. Since the dynamics that yields | Δ L | = 2 interactions unavoidably induces | Δ B | = 2 transitions via B − L breaking, these extensions consequentially lead to intriguing processes such as neutron–antineutron ( n – n ‾ ) oscillation. We investigate this intrinsic connection between neutrino mass generation and n – n ‾ oscillation within a number of representative extensions of the Georgi-Glashow model that can yield realistic neutrino masses and mixing parameters. These extensions include the tree-level seesaw mechanism realizations of the Type I, II, and III varieties, as well as the one-loop and two-loop radiative neutrino mass models.