Neutrino Mass Models and Leptogenesis

Abstract

In this talk we show how a natural neutrino mass hierarchy can follow from the type I see-saw mechanism, and a natural neutrino mass degeneracy from the type II see-saw mechanism, where the bi-large mixing angles can arise from either the neutrino or charged lepton sector. We summarize the phenomenological implications of such natural models, and discuss the model building applications of the approach, focussing on the $SU(3)\times SO(10)$ model. We also show that in such type II models the leptogenesis asymmetry parameter becomes proportional to the neutrino mass scale, in sharp contrast to the type I case, which leads to an upper bound on the neutrino mass scale, allowing lighter right-handed neutrinos and hence making leptogenesis more consistent with the gravitino constraints in supersymmetric models.

14 pages, 3 figures, based on invited talks presented at the 10th International Symposium on Particles, Strings and Cosmology (Pascos04), Northeastern University, Boston, August 16-22, 2004 and Nobel Symposium 129 on Neutrino Physics, Haga Slott, Enkoping, Sweden, August 19-24, 2004

References in corpus (16)

• Cosmological Sign of Neutrino CP Violation
• Neutrino Mass Models
• Neutrino Phenomenology -- the case of two right handed neutrinos
• Consequences of Triplet Seesaw for Leptogenesis
• Fermion Masses and Mixing Angles from SU(3) Family Symmetry and Unification
• Type II Leptogenesis and the Neutrino Mass Scale
• Predictions of the most minimal see-saw model
• Sneutrino Inflation in the Light of WMAP: Reheating, Leptogenesis and Flavour-Violating Lepton Decays
• Leptogenesis-MNS Link in Unified Models with Natural Neutrino Mass Hierarchy
• Sneutrino Hybrid Inflation in Supergravity
• From Hierarchical to Partially Degenerate Neutrinos via Type II Upgrade of Type I See-Saw Models
• Lepton Flavour Violation in the Constrained MSSM with Natural Neutrino Mass Hierarchy
• Neutrino Mixing from the Charged Lepton Sector with Sequential Right-Handed Lepton Dominance
• A Natural Framework for Bi-large Neutrino Mixing
• Patterns of Lepton-Flavour Violation Motivated by Decoupling and Sneutrino Inflation
• Global Analysis of a Supersymmetric Pati-Salam Model

Cited by in corpus (1)

• The Seesaw with Many Right-Handed Neutrinos