Quasi-degenerate neutrinos and leptogenesis from L_mu-L_tau

Abstract

We provide a framework for quasi-degenerate neutrinos consistent with a successful leptogenesis, based on the L_mu-L_tau flavor symmetry and its breaking pattern. In this scheme, a fine-tuning is needed to arrange the small solar neutrino mass splitting. Once it is ensured, the atmospheric neutrino mass splitting and the deviation from the maximal atmospheric mixing angle are driven by the same symmetry breaking parameter lambda~0.1, and the reactor angle is predicted to be slightly smaller than lambda, while the Dirac CP phase is generically of order one. Given that the pseudo-Dirac nature of right-handed neutrinos is protected from the flavor symmetry breaking, a small mass splitting can be generated radiatively. For moderate values of tan(beta)~10, this allows for low-scale supersymmetric leptogenesis, overcoming a strong wash-out effect of the quasi-degenerate light neutrinos and evading the gravitino overproduction.

8 pages, 3 figures; (v2) discussion extended and clarified, references added; (v3) typos corrected, matches the published version

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Cited by in corpus (6)

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• Nonzero U_{e3}, CP violation and leptogenesis in a see-saw type softly broken A_4 symmetric model
• Radiatively broken symmetries of nonhierarchical neutrinos
• TeV Scale Resonant Leptogenesis with $L_{\mu }-L_{\tau }$ Gauge Symmetry in the Light of Muon $(g-2)$
• Resonant leptogenesis in (2,2) inverse see-saw realisation
• Searches for heavy neutrinos at multi-TeV muon collider : a resonant leptogenesis perspective