SHORT-BASE-LINE NEUTRINO OSCILLATIONS AND NEUTRINOLESS DOUBLE-BETA DECAY IN THE FRAMEWORK OF 3 NEUTRINO MIXING AND A MASS HIERARCHY

We have analyzed the results of the latest terrestrial neutrino oscill ation experiments in the framework of a model with mixing of three mas sive neutrinos and a neutrino mass hierarchy (m(1) much less than m(2) much less than 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 an d U-mu 3. Using the results of disappearance experiments and solar neu trino experiments, it is shown that only two regions of possible value s 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 larg e. If the mixing parameters are in region I, nu(mu)reversible arrow nu (e) oscillations are suppressed. In this case the LSND indication in f avor of nu(mu)reversible arrow nu(e) oscillations is not compatible wi th the negative results of all other experiments. If the mixing parame ters are in region II, nu(e) reversible arrow nu(tau) oscillations are strongly suppressed If massive neutrinos are Majorana particles, our analysis shows that neutrinoless double-beta decay could be observed i n the experiments of the next generation only if the mixing parameters are in region I.