| 1. |
- Hällgren, Tomas, et al.
(författare)
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Neutrino oscillations in deconstructed dimensions
- 2005
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Ingår i: Journal of High Energy Physics (JHEP). - : IOP Publishing. - 1126-6708 .- 1029-8479. ; 2005:02, s. 049-
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Tidskriftsartikel (refereegranskat)abstract
- We present a model for neutrino oscillations in the presence of a deconstructed non-gravitational large extra dimension compactified on the boundary of a two-dimensional disk. In the deconstructed phase, sub-mm lattice spacings are generated from the hierarchy of energy scales between similar to 1 TeV and the usual B - L breaking scale similar to 10(15) GeV. Here, short-distance cutoffs down to similar to 1eV are motivated by the strong coupling behavior of gravity in local discrete extra dimensions. This could make it possible to probe the discretization of extra dimensions and non-trivial field configurations in theory spaces which have only a few sites, i.e., for coarse latticizations. Thus, the model has relevance to present and future precision neutrino oscillation experiments.
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| 2. |
- Lindner, Manfred, et al.
(författare)
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Seesaw mechanisms for Dirac and Majorana neutrino masses
- 2002
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Ingår i: Physical Review D. Particles and fields. - : The American Physical Society. - 0556-2821 .- 1089-4918. ; 65:5, s. 053014-
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the seesaw mechanism for generally non-fine-tuned n x n mass matrices involving both Dirac and Majorana neutrinos. We specifically show that the number of naturally light neutrinos cannot exceed half of the dimension of the considered mass matrix. Furthermore, we determine a criterion for mass matrix textures leading to light Dirac neutrinos with the seesaw mechanism. In particular, we study 4 x 4 and 6 x 6 mass matrix textures and give some examples in order to highlight these types of texture. Next, we present a model scheme based on non-Abelian and discrete symmetries satisfying the above mentioned criterion for light Dirac neutrinos. Finally, we investigate the connection between symmetries and the invariants of a mass matrix on a formal level.
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| 3. |
- Ohlsson, Tommy, 1973-, et al.
(författare)
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A flavor symmetry model for bilarge leptonic mixing and the lepton masses
- 2002
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Ingår i: Nuclear Physics B. - : Elsevier Science B.V.. - 0550-3213 .- 1873-1562. ; 643:03-jan, s. 247-279
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Tidskriftsartikel (refereegranskat)abstract
- We present a model for leptonic mixing and the lepton masses based on flavor symmetries and higher-dimensional mass operators. The model predicts bilarge leptonic mixing (i.e., the mixing angles theta(12) and theta(23) are large and the mixing angle theta(13) is small) and an inverted hierarchical neutrino mass spectrum. Furthermore, it approximately yields the experimental hierarchical mass spectrum of the charged leptons. The obtained values for the leptonic mixing parameters and the neutrino mass squared differences are all in agreement with atmospheric neutrino data, the Mikheyev-Smirnov-Wolfenstein large mixing angle solution of the solar neutrino problem, and consistent with the upper bound on the reactor mixing angle. Thus, we have a large, but not close to maximal, solar mixing angle theta(12), a nearly maximal atmospheric mixing angle theta(23), and a small reactor mixing angle theta(13). In addition, the model predicts theta(12) similar or equal to pi/4 - theta(13).
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| 4. |
- Ohlsson, Tommy, 1973-, et al.
(författare)
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Bilarge leptonic mixing from Abelian horizontal symmetries
- 2002
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Ingår i: Physics Letters B. - : Elsevier Science B.V.. - 0370-2693 .- 1873-2445. ; 537:02-jan, s. 95-102
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Tidskriftsartikel (refereegranskat)abstract
- We construct and present a model for leptonic mixing based on higher-dimensional operators, using the Froggatt-Nielsen mechanism. and Abelian horizontal symmetries (flavor symmetries) of continuous and discrete type. Our model naturally yields bilarge leptonic mixing. coming from both the charged leptons and the neutrinos, and an inverted neutrino mass hierarchy spectrum. The obtained values of the parameters, i.e.. the leptonic mixing parameters and the neutrino mass squared differences, are all consistent with the atmospheric neutrino data and the Mikheyev-Smirnov-Wolfenstein large mixing angle solution for the solar neutrino problem.
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| 5. |
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