Majorana neutrino masses in the scenario of gauge-Higgs unification

作者：Hasegawa K^*; Lim C S

来源：Progress of Theoretical and Experimental Physics, 2018, 2018(7): 073B01.

DOI：10.1093/ptep/pty072

In this paper we consider possible mechanisms to generate small Majorana neutrino masses for active neutrinos in the scenario of gauge-Higgs uniflcation, a candidate for physics beyond the standard model. We stress that it is non-trivial to And a gauge-invariant operator, responsible for the Majorana masses, which is the counterpart of the well-known SU(2)(L) x U(l)(y) invariant higher-mass-dimensional (d = 5) operator. As the flrst possibility we discuss the seesaw mechanism by assigning leptonic flelds to the adjoint representation of the gauge group, so that a d = 5 gauge-invariant operator can be formed. It turns out that the mechanism leading to the small Majorana masses is the admixture of the Type I and Type III seesaw mechanisms. As the second possibility, we consider the case where the relevant operator has d = 7, by introducing a matter scalar belonging to the fundamental representation of the gauge group. Reflecting the fact that the mass dimension of the operator is higher than usually expected, the Majorana masses are generated by a "double seesaw mechanism."

• 出版日期2018-7