Constraints on neutrino masses from leptogenesis models

By T. Hambye, Y. Lin, A. Notari, Alessandro Strumia. 2003

208 citations recorded by the source corpus.

Abstract Upper bounds on the CP asymmetry relevant for leptogenesis are reexamined and found weaker than in previous literature, both for hierarchical and for quasi-degenerate right-handed neutrinos. Successful leptogenesis implies the usual lower bound on right-handed neutrino masses, and an upper bound on left-handed neutrino masses (which we obtain to be 0.15 eV at 3σ) only if right-handed neutrinos are assumed to be much more hierarchical than left-handed neutrinos. Otherwise both bounds can be considerably relaxed. The constraint on light neutrino masses varies assuming different interpretations of why neutrinos should be quasi-degenerate. With conservative assumptions, we find that a mild quasi-degeneracy allows neutrinos heavier than an eV compatibly with leptogenesis. We also extend computations of thermal leptogenesis to an alternative model of neutrino mass mediated by fermion triplets which was never considered so far for leptogenesis. Leptogenesis can be successful despite the effect of gauge interactions, resulting in only slightly stronger constraints on neutrino masses.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/c0c022b83aa6f2c92c4b71d2c85c942b99b9ac72

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Citations in the corpus

Neutrinoless double beta decay in seesaw models (2010, background): “They are known as “seesaw” mechanisms of type-I [37–40], where the heavy particles are fermion singlets, type-II [78– 82], where scalars triplets are included, and type-III [83–86], where the SM is extended by fermion triplets.”
A facility to search for hidden particles at the CERN SPS: the SHiP physics case (2015, methodology): “The measurement of such a ratio could then easily rule-out or strongly support the type-III scenario as possible explanation of these processes.”
Leptogenesis in the Universe (2012, background): “This mechanism necessarily involves lepton number violation, and allows for new CP-violating phases so we should examine it as a possible source of leptogenesis [237, 238, 228, 239, 240, 241, 242, 243].”
Leptogenesis (2008, unknown): “There is no similar information in [162], where contrary claims are made.”