Speaker
Wee Hao Ng
(C)
Description
The simplest lepton models based on $A_4$ symmetry predict $\theta_{13} = 0$ at tree level, which contradicts recent experimental data from Daya Bay and RENO. We study models where the $A_4$ symmetry arises as the unbroken subgroup of a spontaneous broken $SO(3)$ symmetry, and find that a nonzero $\theta_{13}$ arises naturally at tree level. Extra heavy fields required in the model mixes with the charged leptons, generating $\theta_{13}$ of order the ratio of the $A_4$-breaking and $SO(3)$-breaking scales.
Author
Wee Hao Ng
(C)
Co-author
Yuval Grossman
(Cornell)
