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Type I seesaw mechanism for quasi-degenerate neutrinos

Joshipura, Anjan S and Patel, Ketan M and Vempati, Sudhir K (2010) Type I seesaw mechanism for quasi-degenerate neutrinos. In: Physics Letters B, 690 (3). pp. 289-295.

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Official URL: http://dx.doi.org/10.1016/j.physletb.2010.05.034


We discuss symmetries and scenarios leading to quasi-degenerate neutrinos in type I seesaw models. The existence of degeneracy in the present approach is not linked to any specific structure for the Dirac neutrino Yukawa coupling matrix y(D) and holds in general. Basic input is the application of the minimal flavour violation principle to the leptonic sector. Generalizing this principle, we assume that the structure of the right-handed neutrino mass matrix is determined by y(D) and the charged lepton Yukawa coupling matrix y(l) in an effective theory invariant under specific groups G(F) contained in the full symmetry group of the kinetic energy terms. G(F) invariance also leads to specific structure for the departure from degeneracy. The neutrino mass matrix (with degenerate mass m(0)) resulting after seesaw mechanism has a simple form Mv approximate to m(0)(I - py(l)y(l)(T)) in one particular scenario based on supersymmetry. This form is shown tolead to correct description of neutrino masses and mixing angles. The thermal leptogenesis after inclusion of flavour effects can account for the observed baryon asymmetry of the universe within the present scenario. Rates for lepton flavour violating processes can occur at observable levels in the supersymmetric version of the scenario. (c) 2010 Elsevier B.V. All rights reserved.

Item Type: Journal Article
Publication: Physics Letters B
Publisher: Elsevier Science
Additional Information: Copyright of this article belongs to Elsevier Science.
Keywords: Neutrino mass;Neutrino mixing angle;Minimal flavour violation;Flavour symmetry;Leptogenesis
Department/Centre: Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Date Deposited: 22 Jul 2010 06:33
Last Modified: 19 Sep 2010 06:11
URI: http://eprints.iisc.ac.in/id/eprint/30380

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