A to Z of Flavour with PatiSalam
Abstract
We propose an elegant theory of flavour based on A _{4} × Z _{5} family symmetry with PatiSalam unification which provides an excellent description of quark and lepton masses, mixing and CP violation. The A _{4} symmetry unifies the lefthanded families and its vacuum alignment determines the columns of Yukawa matrices. The Z _{5} symmetry distinguishes the righthanded families and its breaking controls CP violation in both the quark and lepton sectors. The PatiSalam symmetry relates the quark and lepton Yukawa matrices, with Y ^{ u } = Y ^{ ν } and Y ^{ d } ~ Y ^{ e }. Using the seesaw mechanism with very hierarchical righthanded neutrinos and CSD4 vacuum alignment, the model predicts the entire PMNS mixing matrix and gives a Cabibbo angle θ _{ C } ≈ 1/4. In particular, for a discrete choice of Z _{5} phases, it predicts maximal atmospheric mixing, θ {_{23}/^{ l }} = 45° ± 0.5° and leptonic CP violating phase δ ^{ l } = 260° ± 5°. The reactor angle prediction is θ {_{13}/^{ l }} = 9° ± 0.5°, while the solar angle is 34° ≳ θ {_{12}/^{ l }} ≳ 31°, for a lightest neutrino mass in the range 0 ≲ m _{1} ≲ 0.5 meV, corresponding to a normal neutrino mass hierarchy and a very small rate for neutrinoless double beta decay.
 Publication:

Journal of High Energy Physics
 Pub Date:
 August 2014
 DOI:
 10.1007/JHEP08(2014)130
 arXiv:
 arXiv:1406.7005
 Bibcode:
 2014JHEP...08..130K
 Keywords:

 Neutrino Physics;
 Discrete and Finite Symmetries;
 High Energy Physics  Phenomenology
 EPrint:
 38 pages, 28 figures, published version