Double beta decay and neutrino mass models

• Published in: The journal of high energy physics 2015-05, Vol.2015 (5), p.1-40, Article 92
• Main Authors: Helo, J. C., Hirsch, M., Ota, T., dos Santos, F. A. Pereira
• Format: Article
• Language: English
• Subjects: Beta decay; Classical and Quantum Gravitation; Classification; Concretes; Decay rate; Elementary Particles; Gages; High energy physics; Neutrinos; Phenomenology; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Regular Article - Theoretical Physics; Relativity Theory; Standard model (particle physics); String Theory
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP05(2015)092

A bstract Neutrinoless double beta decay allows to constrain lepton number violating extensions of the standard model. If neutrinos are Majorana particles, the mass mechanism will always contribute to the decay rate, however, it is not a priori guaranteed to be the dominant contribution in all models. Here, we discuss whether the mass mechanism dominates or not from the theory point of view. We classify all possible (scalar-mediated) short-range contributions to the decay rate according to the loop level, at which the corresponding models will generate Majorana neutrino masses, and discuss the expected relative size of the different contributions to the decay rate in each class. Our discussion is general for models based on the SM group but does not cover models with an extended gauge. We also work out the phenomenology of one concrete 2-loop model in which both, mass mechanism and short-range diagram, might lead to competitive contributions, in some detail.