Neutrinoless Double Beta Decay in the Presence of Light Sterile Neutrinos

Abstract

We investigate the predictions for neutrinoless double beta ($({\hat{I}}^2{\hat{I}}^2{)}_{0\hat{I}½}$-) decay effective Majorana mass $\left|⟨m⟩\right|$ in the 3+1 and 3+2 schemes with one and two additional sterile neutrinos with masses at the eV scale. The two schemes are suggested by the neutrino oscillation interpretation of the reactor neutrino and Gallium "anomalies" and of the data of the LSND and MiniBooNE experiments. We analyse in detail the possibility of a complete or partial cancellation between the different terms in $\left|⟨m⟩\right|$, leading to a strong suppression of $\left|⟨m⟩\right|$. We determine the regions of the relevant parameter spaces where such a suppression can occure. This allows us to derive the conditions under which the effective Majorana mass satisfies $\left|⟨m⟩\right|>0.01$ eV, which is the range planned to be exploited by the next generation of $({\hat{I}}^2{\hat{I}}^2{)}_{0\hat{I}½}$-experiments.

36 pages, 22 figures, 5 tables, results unchanged, discussion of cosmological constraints on sterile neutrinos added, the presentation of figures 7, 13, 17 and 21 changed; version to be published in JHEP