The Seesaw Mechanism in Quark-Lepton Complementarity

Abstract

We systematically construct realistic mass matrices for the type-I seesaw mechanism out of more than 20 trillion possibilities. We use only very generic assumptions from extended quark-lepton complementarity, i.e., the leptonic mixing angles between flavor and mass eigenstates are either maximal, or parameterized by a single small quantity epsilon that is of the order of the Cabibbo angle epsilon theta_C. The small quantity epsilon also describes all fermion mass hierarchies. We show that special cases often considered in the literature, such as having a symmetric Dirac mass matrix or small mixing among charged leptons, constitute only a tiny fraction of our possibilities. Moreover, we find that in most cases the spectrum of right-handed neutrino masses is only mildly hierarchical. As a result, we provide for the charged leptons and neutrinos a selected list of 1981 qualitatively different Yukawa coupling matrices (or textures) that are parameterized by the Cabibbo angle and allow for a perfect fit to current data. In addition, we also briefly show how the textures could be generated in explicit models from flavor symmetries.

40 pages, 9 figures, 5 tables. Several typos corrected and references added, final version to appear in PRD. A complete list of the 1981 normal hierarchy textures can be obtained at http://theorie.physik.uni-wuerzburg.de/~winter/Resources/SeeSawTex/

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Cited by in corpus (7)

• Four Zero Neutrino Yukawa Textures in the Minimal Seesaw Framework
• Group space scan of flavor symmetries for nearly tribimaximal lepton mixing
• Mapping out SU(5) GUTs with non-Abelian discrete flavor symmetries
• Unified parametrization of quark and lepton mixing matrices in tri-bimaximal pattern
• Neutrino Oscillation Observables from Mass Matrix Structure
• Fermion masses and neutrino mixing in an U(1)_H flavor symmetry model with hierarchical radiative generation for light charged fermion masses
• Constructing Textures in Extended Quark-Lepton Complementarity