Leptogenesis with an almost conserved lepton number

Abstract

Seesaw models with a slightly broken lepton number symmetry can explain small neutrino masses, and allow for low-scale leptogenesis. We make a thorough analysis of leptogenesis within the simplest model with two right-handed (RH) neutrinos (or with N_3 decoupled). We obtain a semi-analytical formula for the final asymmetry in both supersymmetric and non-supersymmetric cases with a simple dependence on each parameter. The low-energy parameters factorize from the high-energy ones, and the high-energy phase must be non-zero. The role of the PMNS phases is carefully studied. Moreover, we find that the breaking parameter in the Yukawa coupling matrix must be relatively large, ε_h > 10^{-3} for normal and 10^{-2} for inverted hierarchy. Therefore, leptogenesis in our simple model is incompatible with RH neutrino signals at future colliders or sizable lepton-flavor violation. The other breaking parameter, ε_M, which appears in the RH neutrino mass matrix, can be much smaller, and actually needs to be so in order to have low-scale leptogenesis.

Footnote added; Factor of 2 in the supersymmetric case corrected

References in corpus (24)

• The Cosmological Parameters 2006
• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• Leptogenesis
• Phenomenology with Massive Neutrinos
• The importance of flavor in leptogenesis
• Flavour Issues in Leptogenesis
• Right-Handed Neutrinos at LHC and the Mechanism of Neutrino Mass Generation
• A possible symmetry of the $\nu$MSM
• Signatures for Majorana neutrinos at hadron colliders
• Constraints on the Reheating Temperature in Gravitino Dark Matter Scenarios
• Flavor effects on leptogenesis predictions
• Heavy neutrino signals at large hadron colliders
• Leptogenesis and Low Energy CP Violation in Neutrino Physics
• Connecting Low Energy Leptonic CP-violation to Leptogenesis
• Flavour-Dependent Leptogenesis with Sequential Dominance
• The importance of N2 leptogenesis
• A new bridge between leptonic CP violation and leptogenesis
• Leptogenesis beyond the limit of hierarchical heavy neutrino masses
• New aspects of leptogenesis bounds
• Towards constraints on the SUSY seesaw from flavour-dependent leptogenesis
• Viability of Dirac phase leptogenesis
• Successful Leptogenesis in SO(10) Unification with a Left-Right Symmetric Seesaw Mechanism
• Effects of Lightest Neutrino Mass in Leptogenesis
• Leptogenesis, neutrino mixing data and the absolute neutrino mass scale

Cited by in corpus (15)

• Neutrinos and Collider Physics
• Minimal Flavour Seesaw Models
• Muon conversion to electron in nuclei in type-I seesaw models
• Flavour Covariant Transport Equations: an Application to Resonant Leptogenesis
• Leptogenesis from a GeV Seesaw without Mass Degeneracy
• Probing Leptogenesis at Future Colliders
• The minimal scenario of leptogenesis
• Leptogenesis with TeV Scale Inverse Seesaw in SO(10)
• The Little Review on Leptogenesis
• Reconciling leptogenesis with observable mu --> e gamma rates
• Leptogenesis with small violation of B-L
• Resonant Dirac leptogenesis on throats
• Leptogenesis without violation of B-L
• Minimal lepton flavor violating realizations of minimal seesaw models
• Comprehensive Analysis of Charged Lepton Flavour Violation in the Symmetry Protected Type-I Seesaw