Type I+III Seesaw Mechanism and CP Violation for Leptogenesis

Abstract

A seesaw mechanism is presented in the neutrino sector and a new phase of CP violation ($\alpha$) emerges in the interplay between the type-I and type-III seesaw schemes. This phase is inside the mixing term, and thus it cannot be rotated away in the Yukawa Lagrangian and, therefore, the heavy symmetry states cannot be in a diagonal weak basis in the broken phase. Some particular descriptions are analyzed suggesting that if the usual Yukawa couplings are suppressed, leptogenesis still occurs due to a new interacting vertex with fermion triplet $T$, fermion singlets $N$, and an ad-hoc scalar triplet, $\Sigma$, which now is included to mediate the interactions. The evaluated CP violation is enough to generate the observed matter-antimatter asymmetry even in the minimal $1N+1T$ case (independently of $\alpha$) or in the $2N+1T$ approach (controlled by $\alpha$). The latter introduces more CP contributions to leptogenesis due to new diagrams which are now possible even with the suppressed imaginary part of the standard Yukawa couplings and can induce the observed baryon-to-photon ratio.

9 pages, 10 figures; title changed, typos corrected, matches with the published version in PRD

References in corpus (18)

• Leptogenesis
• Big-Bang Nucleosynthesis and Gravitino
• Flavour Matters in Leptogenesis
• Leptogenesis and Low Energy CP Violation in Neutrino Physics
• Connecting Low Energy Leptonic CP-violation to Leptogenesis
• Flavour Covariant Transport Equations: an Application to Resonant Leptogenesis
• Probing seesaw at LHC
• Flavoured leptogenesis: a successful thermal leptogenesis with N_1 mass below 10^8 GeV
• Neutrino Masses, Lepton Flavor Mixing and Leptogenesis in the Minimal Seesaw Model
• Renormalizable Adjoint SU(5)
• The importance of N2 leptogenesis
• A new bridge between leptonic CP violation and leptogenesis
• Upper Bound on the Mass of the Type III Seesaw Triplet in an SU(5) Model
• A Minimal Type II Seesaw Model
• Successful $N_2$ leptogenesis with flavour coupling effects in realistic unified models
• Reactor mixing angle from hybrid neutrino masses
• SU(5)xSU(5) unification revisited
• New Solution for Neutrino Masses and Leptogenesis in Adjoint SU(5)

Cited by in corpus (10)

• Lepton Number Violation and `Diracness' of massive neutrinos composed of Majorana states
• Mixed Inert Scalar Triplet Dark Matter, Radiative Neutrino Masses and Leptogenesis
• Leptogenesis, radiative neutrino masses and inert Higgs triplet dark matter
• Leptogenesis in fast expanding Universe
• Effective Operator Bases for Beyond Standard Model Scenarios: An EFT compendium for discoveries
• Peccei-Quinn symmetry for Dirac seesaw and leptogenesis
• From high-scale leptogenesis to low-scale one-loop neutrino mass generation
• A hybrid seesaw model and hierarchical neutrino flavor structures based on $A_4$ symmetry
• Minimal Leptogenesis in Brane-inspired Cosmology
• Hybrid seesaw neutrino model in SUSY $SU(5)\times {\mathbb{A}}_4$