The neutrinoless double beta decay of 76Ge, 82Se, 86Kr, 114Cd, 128, 130Te and 134, 136Xe in the framework of a relativistic quark confinement model

Abstract

The half-life of the 0 + → 0 + neutrinoless double beta decay is calculated for 76Ge, 82Se, 86Kr, 114Cd, 128, 130Te and 134, 136Xe 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 |〈 Λ〉| < 4.1 × 10 −6 and |〈 ν〉| < 6.6 × 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.