F-theory and Neutrinos: Kaluza-Klein Dilution of Flavor Hierarchy

We present a Majorana neutrino scenario in a F‐theory SU(5) GUT model, which is recently proposed in [1]. The mass scale of the neutrinos arises from integrating out heavy Kaluza‐Klein modes on the right‐handed neutrinos. The participation of non‐holomorphic Kaluza‐Klein mode wave functions dilutes the mass hierarchy in comparison to the quark and charged lepton sectors, in agreement with experimentally measured mass splittings. The neutrinos are predicted to exhibit a “normal” mass hierarchy, with masses (m3, m2, m1) ∼.05×(1,αGUT1/2,αGUT) eV. The neutrino mixing matrix exhibits a mild hierarchical structure with θ13∼αGUT1/2∼0.2. We also predict mass measurements in single and double beta decay experiments.