Short-baseline neutrino oscillations and neutrinoless double-beta decay in the framework of three neutrino mixing and a mass hierarchy

Abstract

We have analyzed the results of the latest terrestrial neutrino oscillation experiments in the framework of a model with mixing of three massive neutrinos and a neutrino mass hierarchy ($m_1<<m_2<<m_3$). In this model, oscillations of the terrestrial neutrinos are characterized by three parameters, $\Delta m^2=m_3^2-m_1^2$ and the squared moduli of the two mixing matrix elements $U_{e3}$ and $U_{\mu 3}$. Using the results of disappearance experiments and solar neutrino experiments, it is shown that only two regions of possible values of $|U_{e3}{|}^2$ and $|U_{\mu 3}{|}^2$ are allowed: I. $|U_{e3}{|}^2$ and $|U_{\mu 3}{|}^2$ are both small and II. $|U_{e3}{|}^2$ is small and $|U_{\mu 3}{|}^2$ is large. If the mixing parameters are in the region I, ${\nu }_{\mu }<->{\nu }_e$ oscillations are suppressed. In this case the LSND indication in favor of ${\nu }_{\mu }<->{\nu }_e$ oscillations is not compatible with the negative results of all other experiments. If the mixing parameters are in the region II, ${\nu }_e<->{\nu }_{\tau }$ oscillations are strongly suppressed. If massive neutrinos are Majorana particles, our analysis shows that neutrinoless double-beta decay could be observed in the experiments of the next generation only if the mixing parameters are in the region I.

Comments: RevTeX file, 26 pages including 9 figures. The postscript file is available at http://www.to.infn.it/teorici/giunti/papers.html