Double beta decay in left-right symmetric models

Abstract

Left-right symmetric models provide a natural framework for neutrinoless double beta ($\text{znbb}$) decay. In the analysis of $\text{znbb}$ decay in left-right symmetric models, however, it is usually assumed that all neutrinos are light. On the other hand, heavy {\it 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 $\text{znbb}$ decay of ${}^{76}$Ge currently provides the following limits on the mass and mixing angle of right-handed W-bosons: $m_{W_R}\ge 1.1$ TeV and $\tan (\zeta )\le 4.7\times 10^{-3}$ for a particular value of the effective right-handed neutrino mass, $\text{emnv}=1$ TeV, and in the limit of infinitly massive doubly charged Higgs (${\Delta }^{--}$). The effects of the inclusion of the Higgs triplet on $\text{znbb}$ decay are also discussed.

Comments: LaTeX, 9 pages, 3 figures