Systematic classification of two-loop realizations of the Weinberg operator

Autor: Sierra, D. Aristizabal, Degee, A., Dorame, L., Hirsch, M.
Rok vydání: 2014
Předmět:
Zdroj: JHEP 1503, 040 (2015)
Druh dokumentu: Working Paper
DOI: 10.1007/JHEP03(2015)040
Popis: We systematically analyze the $d=5$ Weinberg operator at 2-loop order. Using a diagrammatic approach, we identify two different interesting categories of neutrino mass models: (i) Genuine 2-loop models for which both, tree-level and 1-loop contributions, are guaranteed to be absent. And (ii) finite 2-loop diagrams, which correspond to the 1-loop generation of some particular vertex appearing in a given 1-loop neutrino mass model, thus being effectively 2-loop. From the large list of all possible 2-loop diagrams, the vast majority are infinite corrections to lower order neutrino mass models and only a moderately small number of diagrams fall into these two interesting classes. Moreover, all diagrams in class (i) are just variations of three basic diagrams, with examples discussed in the literature before. Similarly, we also show that class (ii) diagrams consists of only variations of these three plus two more basic diagrams. Finally, we show how our results can be consistently and readily used in order to construct two-loop neutrino mass models.
Comment: Few clarifications and references added. Matches published version in JHEP
Databáze: arXiv