Recently T2K experiment gives hint in favor of large reactor angle θ13. Most of the models, with ... more Recently T2K experiment gives hint in favor of large reactor angle θ13. Most of the models, with tribimaximal mixing at the leading order, can not reproduce such a large mixing angle since they predict typically corrections for the reactor angle of the order θ13˜λC2, where λC˜0.2. In this paper, we discuss the possibility to achieve large θ13 within the T2K region with maximal atmospheric mixing angle, sin2θ23=1/2, and trimaximal solar mixing angle, sin2θ12=1/3, through the deviation from the exact tribimaximal mixing. We derive the structure of neutrino mass matrix that leads to the large θ13 leaving maximal θ23 and trimaximal θ12. It is shown that such a structure of neutrino mass matrix can arise in a model with S4 flavor symmetry.
We study the flavour sector in models where the three families of matter are unified in a $(16,3)... more We study the flavour sector in models where the three families of matter are unified in a $(16,3)$ representation of the $SO(10)\times A_4$ group. The necessary ingredients to realize tri-bi-maximal mixing in the lepton sector are identified systematically. The non-renormalizable operators contributing to the fermion mass matrices play an important role. We also present a mechanism to explain the inter-family mass hierarchy of quarks and charged leptons, which relies on a `universal seesaw' mechanism and is compatible with tri-bi-maximal mixing.
We study an extension of the standard model based on the flavor symmetry A4 only. Neutrino Majora... more We study an extension of the standard model based on the flavor symmetry A4 only. Neutrino Majorana mass terms arise from a dimension five operator and charged lepton masses from renormalizable Yukawa couplings. We introduce three Higgs doublets that belong to one triplet irreducible representation of A4. We study the most general A4-invariant scalar potential and the phenomenological consequences of the model. We find that the reactor angle could be as large as sinf 2theta13maxf ˜0.03, while the atmospheric mixing angle theta23 is close to maximal, sinf 2theta23=1/2.
ABSTRACT We propose that dark matter is stable as a consequence of an accidental Z2 that results ... more ABSTRACT We propose that dark matter is stable as a consequence of an accidental Z2 that results from a flavour-symmetry group which is the double-cover group of the symmetry group of one of the regular geometric solids. Although model-dependent, the phenomenology resembles that of a generic Higgs portal dark matter scheme.
Recently T2K experiment gives hint in favor of large reactor angle θ13. Most of the models, with ... more Recently T2K experiment gives hint in favor of large reactor angle θ13. Most of the models, with tribimaximal mixing at the leading order, can not reproduce such a large mixing angle since they predict typically corrections for the reactor angle of the order θ13˜λC2, where λC˜0.2. In this paper, we discuss the possibility to achieve large θ13 within the T2K region with maximal atmospheric mixing angle, sin2θ23=1/2, and trimaximal solar mixing angle, sin2θ12=1/3, through the deviation from the exact tribimaximal mixing. We derive the structure of neutrino mass matrix that leads to the large θ13 leaving maximal θ23 and trimaximal θ12. It is shown that such a structure of neutrino mass matrix can arise in a model with S4 flavor symmetry.
We study the flavour sector in models where the three families of matter are unified in a $(16,3)... more We study the flavour sector in models where the three families of matter are unified in a $(16,3)$ representation of the $SO(10)\times A_4$ group. The necessary ingredients to realize tri-bi-maximal mixing in the lepton sector are identified systematically. The non-renormalizable operators contributing to the fermion mass matrices play an important role. We also present a mechanism to explain the inter-family mass hierarchy of quarks and charged leptons, which relies on a `universal seesaw' mechanism and is compatible with tri-bi-maximal mixing.
We study an extension of the standard model based on the flavor symmetry A4 only. Neutrino Majora... more We study an extension of the standard model based on the flavor symmetry A4 only. Neutrino Majorana mass terms arise from a dimension five operator and charged lepton masses from renormalizable Yukawa couplings. We introduce three Higgs doublets that belong to one triplet irreducible representation of A4. We study the most general A4-invariant scalar potential and the phenomenological consequences of the model. We find that the reactor angle could be as large as sinf 2theta13maxf ˜0.03, while the atmospheric mixing angle theta23 is close to maximal, sinf 2theta23=1/2.
ABSTRACT We propose that dark matter is stable as a consequence of an accidental Z2 that results ... more ABSTRACT We propose that dark matter is stable as a consequence of an accidental Z2 that results from a flavour-symmetry group which is the double-cover group of the symmetry group of one of the regular geometric solids. Although model-dependent, the phenomenology resembles that of a generic Higgs portal dark matter scheme.
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