Yukawa textures, neutrino masses and Horava–Witten M-theory Original Research Article

We consider the Horava–Witten based model with 5-branes situated near the distant orbifold plane and with vanishing instanton numbers on the physical plane. This model has a toric fibered Calabi–Yau with del Pezzo base dP7 which allows three generations with Standard Model gauge group at the GUT scale. Previous analysis showed that the quark hierarchy at the electroweak scale could be achieved qualitatively without undue fine tuning due to the effects of the 5-branes on the Kahler potential. We extend here this analysis to include the leptons. A new mechanism is introduced to obtain neutrino masses by assuming massless right handed neutrinos exist in the particle spectrum, which allows a cubic holomorphic term to exist in the Kahler metric, lLH2νR, scaled by the 11D Planck mass. After transferring this term to the superpotential, this term gives rise to neutrino masses of the correct size at the electroweak scale. With natural choices of the Yukawa and Kahler matrix entries, it is possible to fit all mass, CKM and MNS experimental data. The model predicts μ→e+γ decay at a rate that should be detectable for much of the SUSY parameter space in the next round of experiments.