Majorana neutrino mass structure induced by rigid instatons on toroidal orbifold

Understand

We study effects of D-brane instantons wrapping rigid cycles on Z2*Z2' toroidal orbifold.

• We compute Majorana masses induced by rigid D-brane instantons and realize bimaximal mixing matrices in certain models.
• We can also derive more generic mass matrices in other models.
• The bimaximal mixing Majorana mass matrix has a possibility to explain observed mixing angles.