We revisit an extension of the Standard Model with Majorana fermions in adjoint representations, where SU(2)L triplet and SU(3)c octet fermions are introduced. The model provides not only a precise coupling unification but also a dark matter candidate [an SU(2)L triplet fermion]. In particular, we show that an SU(3)c octet fermion, which is required for successful unification, can be a good nonthermal source of the triplet fermion dark matter. We also show that the scenario predicts a rather short lifetime of the proton compared with the minimal supersymmetric grand unified theory, and the most parameter space can be explored by future experiments such as the Hyper-Kamiokande experiment.
|Original language||English (US)|
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|State||Published - Apr 17 2015|
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© 2015 American Physical Society.