CP Asymmetry in Majorana Neutrino Decays
Year: 1997
Type: preprint
Abstract: We study CP asymmetries in lepton-number violating two-body scattering processes and show how they are related to CP asymmetries in the decays of the intermediate massive Majorana neutrinos. We demonstrate that self-energy corrections do not contribute to CP asymmetries in leading order. Decays of heavy Majorana neutrinos may be responsible for most of the cosmological baryon asymmetry [1]. As detailed studies have shown, the observed asymmetry nB/s ∼ 10−10 is naturally obtained for theoretically well motivated patterns of neutrino masses and mixings, without [2,3,4] and with [5,6] supersymmetry. The CP asymmetry in Majorana neutrino decays is conventionally evaluated from the interference between the tree diagram and the one-loop vertex correction [7]. Recently, this procedure has been challenged, and it has been argued that also the interference between the tree diagram and the self-energy corrections has to be taken into account [9–11]. This question is important since the self-energy contributions appear to have a large effect in some cases [12]. In the following we shall investigate this problem. We find that self-energy corrections have no effect on observable CP asymmetries.
Authors: W. Buchmüller, M. Plümacher
Institution: Deutsches Elektronen-Synchrotron DESY
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3100361248