Relating small neutrino masses and mixing

Abstract

Experiments on neutrino oscillations have uncovered several small parameters, ${\theta }_{13}$ being a prominent one. Others are the solar mass splitting {\em vis-à-vis} the atmospheric one and the deviation of ${\theta }_{23}$ from maximal mixing. In this talk we elaborate on a neutrino mass model based on the see-saw mechanism in which the mixing angles to start with are either vanishing (${\theta }_{13}$ and ${\theta }_{12}$) or $\pi /4$ (${\theta }_{23}$). The atmospheric mass splitting is taken as a part of this initial structure but the solar splitting is absent. A perturbative contribution, originating from a Type-I see-saw, results in non-zero values of ${\theta }_{13}$, ${\theta }_{12}$, $\Delta m_{solar}^2$, and shifts ${\theta }_{23}$ slightly from $\pi /4$, interrelating them all. The model incorporates CP-violation, the phase $\delta$ being close to 3$\pi$/2 for (a) quasi-degeneracy or (b) inverted mass ordering. It will be put to test as the neutrino parameters get better determined.

Talk given by A. Raychaudhuri at the International Conference on Massive Neutrinos, IAS, NTU, Singapore, February 2015; to appear in the Proceedings; based closely on arXiv:1411:0320, v2: One typo fixed, v3: Published version, minor typographical changes, references updated

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• Big-Bang Nucleosynthesis
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• Global fit to three neutrino mixing: critical look at present precision
• Testable constraint on near-tribimaximal neutrino mixing
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Cited by in corpus (1)

• A neutrino mass model with S3 symmetry and see-saw interplay