Double beta decay in left-right symmetric models

Abstract

Left-right symmetric models provide a natural framework for neutrinoless double beta (0νββ) decay. In the analysis of 0νββ decay in left-right symmetric models, however, it is usually assumed that all neutrinos are light. On the other hand, heavy right-handed neutrinos appear quite naturally in left-right symmetric models and should therefore not be neglected. Assuming the existence of at least one right-handed heavy neutrino, absence of 0νββ decay of 76Ge currently provides the following limits on the mass and mixing angle of right-handed W-bosons: m W R ≥ 1.1 TeV and tan(ζ) ≤ 4.7 × 10 −3 for a particular value of the effective right-handed neutrino mass, 〈 m N ( V) 〉 = 1 TeV, and in the limit of infinitely massive doubly charged Higgs ( Δ −−). The effects of the inclusion of the Higgs triplet on 0νββ decay are also discussed.