Radiative generation of neutrino mixing: degenerate masses and threshold corrections

Abstract

Degenerate neutrino masses are excluded by experiment. The experimentally measured mass squared differences together with the yet undetermined absolute neutrino mass scale allow for a quasi-degenerate mass spectrum. For the lightest neutrino mass larger than roughly 0.1 eV, we analyse the influence of threshold corrections at the electroweak scale. We show that typical one-loop corrections can generate the observed neutrino mixing as well as the mass differences starting from exactly degenerate masses at the tree-level. Those threshold corrections have to be explicitly flavour violating. Flavour diagonal, non-universal corrections are not sufficient to simultaneously generate the correct mixing and the mass differences. We apply the new insights to an extension of the Minimal Supersymmetric Standard Model with non-minimal flavour violation in the soft breaking terms and discuss the low-energy threshold corrections to the light neutrino mass matrix in that model.

25 pages; references added, minor corrections (typos) and Figs. 3, 4 changed; matches version accepted by PRD

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• Leptogenesis
• Updated fit to three neutrino mixing: status of leptonic CP violation
• Global fit to three neutrino mixing: critical look at present precision
• Seesaw mechanism in the sneutrino sector and its consequences
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• Purely Triplet Seesaw and Leptogenesis within Cosmological Bound, Dark Matter and Vacuum Stability
• Unification Predictions With or Without Supersymmetry
• Neutrinos Meet Supersymmetry: Quantum Aspects of of Neutrinophysics in Supersymmetric Theories
• Revamped Bi-Large neutrino mixing with Gatto-Sartori-Tonin like relation
• Can SUSY relax LNV constraints coming from loop corrections to light neutrino masses on the low-scale Seesaw?