Leptogenesis from first principles in the resonant regime
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22603 Hamburg (Germany)
- Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)
- Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)
The lepton asymmetry generated by the out-of-equilibrium decays of heavy Majorana neutrinos with a quasi-degenerate mass spectrum is resonantly enhanced. In this work, we study this scenario within a first-principle approach. The quantum field theoretical treatment is applicable for mass splittings of the order of the width of the Majorana neutrinos, for which the enhancement is maximally large. The non-equilibrium evolution of the mixing Majorana neutrino fields is described by a formal analytical solution of the Kadanoff-Baym equations, that is obtained by neglecting the back-reaction. Based on this solution, we derive approximate analytical expressions for the generated asymmetry and compare them to the Boltzmann result. We find that the resonant enhancement obtained from the Kadanoff-Baym approach is smaller compared to the Boltzmann approach, due to additional contributions that describe coherent transitions between the Majorana neutrino species. We also discuss corrections to the masses and widths of the degenerate pair of Majorana neutrinos that are relevant for very small mass splitting, and compare the approximate analytical result for the lepton asymmetry with numerical results. - Highlights: Black-Right-Pointing-Pointer Treatment of leptogenesis in the resonant regime by a first-principle approach. Black-Right-Pointing-Pointer Applicable for mass differences of the order of the width. Black-Right-Pointing-Pointer Non-equilibrium evolution described by Kadanoff-Baym equations. Black-Right-Pointing-Pointer Analytical solution can be obtained neglecting backreaction. Black-Right-Pointing-Pointer Resonant enhancement is smaller compared to the classical Boltzmann approach.
- OSTI ID:
- 22157057
- Journal Information:
- Annals of Physics (New York), Vol. 328; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-4916
- Country of Publication:
- United States
- Language:
- English
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