2013/06/30 by Y. H. Ahn, Seungwon Baek · 2 citations
Physics and Astronomy · #hep-ph
paper · pdf · doi:10.1103/physrevd.88.036017
40 pages, 11 figures; version published in Phys. Rev. D. arXiv admin note: substantial text overlap with arXiv:1207.1229, arXiv:1304.0921, arXiv:1303.4863
arxiv created 2013/08/22 · arxiv updated 2013/09/03
We propose a simple model for the spontaneous CP violation based on SU(2)L× U(1)Y× A4× CP× Z2 symmetry for quarks and leptons in a seesaw framework. In our model CP is spontaneously broken at high energies, after breaking of flavor symmetry, by a complex vacuum expectation value of A4-triplet and gauge singlet scalar field. And, certain effective dimension-5 operators are introduced in the quark Lagrangian as an equal footing, which lead the quark mixing matrix to the Cabibbo-Kobayashi-Maskawa (CKM) one in the form, while the lepton Lagrangian is renormalizable, which gives rise to a non-degenerate Dirac neutrino Yukawa matrix and an unique CP-phase, and which in turn explains the non-zero value of θ13≃9∘ and two large mixing angles θ12, θ23. We show that the spontaneously generated CP phase "ξ" could become a natural source of leptogenesis as well as CP violations in the CKM and Pontecorvo-Maki-Nakagawa-Sakata (PMNS). Moreover, we provide a solution for the strong CP problem. Interestingly enough, we show that, for around ξ≃120∘, the quarks lead to the correct CKM CP-phase corresponding to δqCP≃67∘, while the leptons with the measured value of θ13 favor δCP=, |θ23-45∘|→0 for normal mass hierarchy and δCP=, |θ23-45∘|→5∘ for inverted one. As a numerical study in the lepton sector, we show low-energy phenomenologies and leptogenesis for the normal and inverted case, respectively, and a link between them.