On the connection of leptogenesis with low energy CP violation and lepton flavor violating charged lepton decays

Pascoli, S.; Petcov, S.T.; Rodejohann, W.

Abstract

The biunitary parametrization of the neutrino Dirac mass matrix mD of the seesaw mechanism of neutrino mass generation is considered in detail. Assuming a hierarchical structure of mD and of the heavy Majorana neutrino masses M1,2,3>0, M1≪M2≪M3, with a strong hierarchy between M3 and M1 (M3≫103M1), we find that, in order to produce the observed baryon asymmetry of the Universe via leptogenesis, the scale of mD should be given by the up-quark masses, mD∼mup. It is also possible to reproduce the low-energy neutrino mixing phenomenology for mD∼mup if one of the heavy Majorana neutrinos is much heavier than the other two and there exists only a rather mild hierarchy between the masses of the latter (M2≅10 M1). In the case of a strong hierarchy between M3 and M1,2, successful leptogenesis requires a mild hierarchy between M1 and M2 as well. In this scenario, the effective Majorana mass in neutrinoless double beta decay depends on the CP violating phase controlling the leptogenesis if mD1 is negligible. The lepton flavor violating decays μ→e+γ, τ→μ+γ and τ→e+γ are considered and a characteristic relation between their decay rates is predicted. The CP violation effects in neutrino oscillations can be observable. In general, there is no direct connection between the latter and CP violation in leptogenesis. If the CP violating phases of the seesaw model satisfy certain relations, the baryon asymmetry of the Universe and the rephasing invariant JCP which determines the magnitude of the CP violation effects in neutrino oscillations depend on the same CP violating phase and their signs are correlated.

Citation

Pascoli, S., Petcov, S., & Rodejohann, W. (2003). On the connection of leptogenesis with low energy CP violation and lepton flavor violating charged lepton decays. Physical Review D, Particles and fields, 68, https://doi.org/10.1103/physrevd.68.093007

• Journal Article Type: Article
• Publication Date: 2003-11
• Deposit Date: Apr 28, 2008
• Publicly Available Date: Apr 28, 2008
• Journal: Physical Review D, Particles and fields
• Print ISSN: 0556-2821
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 68
• DOI: https://doi.org/10.1103/physrevd.68.093007
• Keywords: Heavy majorana neutrinos, Double-beta decay, Number violation, Oscillation experiments, Baryon asymmetry, Non-conservation, Seesaw model, Baryogenesis, mass, Universe.
• Public URL: https://durham-repository.worktribe.com/output/1556663