THE NEUTRINOLESS DOUBLE BETA-DECAY OF GE-76, SE-82, KR-86, CD-114, TE-128,TE-130 AND XE-134,XE-136 IN THE FRAMEWORK OF A RELATIVISTIC QUARK CONFINEMENT MODEL

The half-life of the 0+ --> 0+ neutrinoless double beta decay is calculated for Ge-76, Se-82, Kr-86, Cd-114, Te-128, Te-130 and Xe-134, Xe-136 and the upper limit for the effective neutrino mass of 3.0 eV is deduced from available experimental data. In addition, the contribution of the right-handed charged weak currents to the effective weak hamiltonian is estimated. The relevant parameters attain the values \<lambda>\ < 4.1 x 10(-6) and \<eta>\ < 6.6 x 10(-8). The nucleonic weak current is treated starting from the current quark level and evaluating the quark current using relativistic quark wave functions obtained from a Dirac equation with a harmonic confinement potential. The nuclear matrix elements of the thus obtained effective weak operators are evaluated using the proton-neutron quasi-particle random phase approximation approach avoiding the use of closure and the accompanying singular neutrino potentials. The dependence of the decay half-life on the recoil effects and the p-wave contribution is analyzed. Detailed presentation of the theory is pursued.