Resonant enhancement in leptogenesis

Dev, P.S.B. and Garny, M. and Klaric, J. and Millington, P. and Teresi, D. (2018) Resonant enhancement in leptogenesis. International Journal of Modern Physics A, 33 (05n06). p. 1842003. ISSN 0217-751X

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Abstract

Vanilla leptogenesis within the type I seesaw framework requires the mass scale of the right-handed neutrinos to be above 109 GeV. This lower bound can be avoided if at least two of the sterile states are almost mass degenerate, which leads to an enhancement of the decay asymmetry. Leptogenesis models that can be tested in current and upcoming experiments often rely on this resonant enhancement, and a systematic and consistent description is therefore necessary for phenomenological applications. In this review article, we give an overview of different methods that have been used to study the saturation of the resonant enhancement when the mass difference becomes comparable to the characteristic width of the Majorana neutrinos. In this limit, coherent flavor transitions start to play a decisive role, and off-diagonal correlations in flavor space have to be taken into account. We compare various formalisms that have been used to describe the resonant regime and discuss under which circumstances the resonant enhancement can be captured by simplified expressions for the CP asymmetry. Finally, we briefly review some of the phenomenological aspects of resonant leptogenesis.

Item Type: Article
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Physics and Astronomy
Identification Number: https://doi.org/10.1142/S0217751X18420034
Depositing User: Eprints, Support
Date Deposited: 16 Mar 2018 14:05
Last Modified: 18 Mar 2018 05:52
URI: http://eprints.nottingham.ac.uk/id/eprint/50480

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