Naturalness and the Neutrino Matrix

Abstract

The observed pattern of neutrino mass splittings and mixing angles indicates that their family structure is significantly different from that of the charged fermions. We investigate the implications of these data for the fermion mass matrices in grand unified theories with a type-I seesaw mechanism. We show that, with simple assumptions, naturalness leads to a strongly hierarchical Majorana mass matrix for heavy right-handed neutrinos and a partially cascade form for the Dirac neutrino matrix. We consider various model building scenarios which could alter this conclusion, and discuss their consequences for the construction of a natural model. We find that including partially lopsided matrices can aid us in generating a satisfying model.

Discussion about neutrinoless double beta decay expanded; typos corrected; references added and updated

References in corpus (29)

• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• The Cosmological Parameters 2006
• Tri-Bimaximal Mixing and the Neutrino Oscillation Data
• Massive neutrinos and cosmology
• Latest Results from the Heidelberg-Moscow Double Beta Decay Experiment
• Running Neutrino Mass Parameters in See-Saw Scenarios
• Limits on the Majorana neutrino mass in the 0.1 eV range
• Fermion masses, neutrino oscillations, and proton decay in the light of SuperKamiokande
• Neutrino masses and mixings and...
• Results from a search for the $0\nu \beta \beta$-decay of ${}^{130}Te$
• Models of Neutrino Masses and Mixings
• A Systematic SO(10) Operator Analysis for Fermion Masses
• A different see-saw formula for neutrino masses
• Bi-Maximal Neutrino Mixing in SO(10)_{GUT}
• Neutrino Oscillations in an SO(10) SUSY GUT with U(2)xU(1)${}^n$ Family Symmetry
• Large Neutrino Mixing from Small Quark and Lepton Mixings
• Mass Matrix Textures From Superstring Inspired SO(10) Models
• Neutrino masses and cosmic radiation density: Combined analysis
• Construction of a Minimal Higgs SO(10) SUSY GUT Model
• Realization of the Large Mixing Angle Solar Neutrino Solution in an SO(10) Supersymmetric Grand Unified Model
• Fermion Masses and Neutrino Oscillations in SO(10) SUSY GUT with D_3 x U(1) Family Symmetry
• Obtaining the large angle MSW solution to the solar neutrino problem in models
• Lopsided Mass Matrices and Leptogenesis in SO(10) GUT
• Hints on the high-energy seesaw mechanism from the low-energy neutrino spectrum
• Neutrino Masses and Mixing, Quark-lepton Symmetry and Strong Right-handed Neutrino Hierarchy
• CP Violation and Neutrino Masses and Mixings from Quark Mass Hierarchies
• Higher-dimensional operators in SUSY SO(10) GUT models
• Perturbative SO(10) GUT and the Minimal Higgs Sector
• Grand Unification with and without Supersymmetry

Cited by in corpus (7)

• Lepton Mixing and Cancellation of the Dirac Mass Hierarchy in SO(10) GUTs with Flavor Symmetries T7 and Sigma(81)
• Group space scan of flavor symmetries for nearly tribimaximal lepton mixing
• Tri-bimaximal Mixing from Cascades
• Probing Yukawa Unification with K and B Mixing
• Flavor Physics in an SO(10) Grand Unified Model
• A general formula by $LD{L}^T$ decomposition for the type-I seesaw mechanism
• Conditions of naturalness and fine-tunings for type-I seesaw mechanism with four-zero texture