Seesaw with Occamʼs Razor

Available online at www.sciencedirect.com

Nuclear Physics B (Proc. Suppl.) 235–236 (2013) 245–248 www.elsevier.com/locate/npbps

Seesaw with Occam's Razor T. Yanagidaa a

Kavli IPMU, TODIAS, University of Tokyo, Kashiwa 277-8583, Japan

Abstract We discuss the seesaw mechanism which includes the minimum number of parameters for successful leptogenesis and three neutrino oscillations in the spirit of Occam's razor. We show that models with two righthanded neutrinos with two texture zeros supported by Occam's razor cannot fit the observed neutrino parameters consistently for the normal light neutrino mass hierarchy. For the inverted light neutrino mass hierarchy, on the other hand, we find that the models can fit the observed neutrino parameters consistently. Besides, we show that the model predicts the maximal Dirac CP-phase of the neutrino mixing matrix in the measurable range in the foreseeable future for the inverted neutrino mass hierarchy. We also show that the predicted effective Majorana neutrino mass responsible for the neutrinoless double beta decay is around 50 meV which is also within reach of future experiments. For details, see Phys.Rev. D86 (2012) 013002.

0920-5632/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.nuclphysbps.2013.04.017

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T. Yanagida / Nuclear Physics B (Proc. Suppl.) 235–236 (2013) 245–248

T. Yanagida / Nuclear Physics B (Proc. Suppl.) 235–236 (2013) 245–248

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T. Yanagida / Nuclear Physics B (Proc. Suppl.) 235–236 (2013) 245–248