Effective Lagrangian approach to neutrinoless double beta decay and neutrino masses

• Published in: The journal of high energy physics 2012-06, Vol.2012 (6), Article 146
• Main Authors: del Aguila, Francisco, Aparici, Alberto, Bhattacharya, Subhaditya, Santamaria, Arcadi, Wudka, Jose
• Format: Article
• Language: English
• Subjects: Beta decay; Chirality; Classical and Quantum Gravitation; Decay rate; Electrons; Elementary Particles; High energy physics; Leptons; Neutrinos; Operators; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Relativity Theory; String Theory
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP06(2012)146

A bstract Neutrinoless double beta (0 νββ ) decay can in general produce electrons of either chirality, in contrast with the minimal Standard Model (SM) extension with only the addition of the Weinberg operator, which predicts two left-handed electrons in the final state. We classify the lepton number violating (LNV) effective operators with two leptons of either chirality but no quarks, ordered according to the magnitude of their contribution to 0 νββ decay. We point out that, for each of the three chirality assignments, e L e L , e L e R and e R e R , there is only one LNV operator of the corresponding type to lowest order, and these have dimensions 5, 7 and 9, respectively. Neutrino masses are always induced by these extra operators but can be delayed to one or two loops, depending on the number of RH leptons entering in the operator. Then, the comparison of the 0 νββ decay rate and neutrino masses should indicate the effective scenario at work, which confronted with the LHC searches should also eventually decide on the specific model elected by nature. We also list the SM additions generating these operators upon integration of the heavy modes, and discuss simple realistic examples of renormalizable theories for each case.