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arXiv · 1107.6002

Leptogenesis in the two right-handed neutrino model revisited

S. Antusch·P. Di Bari·D. A. Jones·S. F. King
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Abstract

We revisit leptogenesis in the minimal non-supersymmetric type I see-saw mechanism with two right-handed (RH) neutrinos, including flavour effects and allowing both RH neutrinos N_1 and N_2 to contribute, rather than just the lightest RH neutrino N_1 that has hitherto been considered. By performing scans over parameter space in terms of the single complex angle z of the orthogonal matrix R, for a range of PMNS parameters, we find that in regions around z \sim \pm π/2, for the case of a normal mass hierarchy, the N_2 contribution can dominate the contribution to leptogenesis, allowing the lightest RH neutrino mass to be decreased by about an order of magnitude in these regions, down to M_1 \sim 1.3*10^11 GeV for vanishing initial N_2-abundance, with the numerical results supported by analytic estimates. We show that the regions around z \sim \pm π/2 correspond to light sequential dominance, so the new results in this paper may be relevant to unified model building.

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S. Antusch, P. Di Bari, D. A. Jones, S. F. King. 2012-08-31. Leptogenesis in the two right-handed neutrino model revisited. https://doi.org/10.1103/physrevd.86.023516

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