l - th / 9 81 00 72 v 1 2 7 O ct 1 99 8 Weak Magnetism in Two Neutrino Double Beta Decay ∗
نویسندگان
چکیده
We have extended the formalism for the two-neutrino double beta decay by including the weak-magnetism term, as well as other second-forbidden corrections. The weak magnetism diminishes the calculated half-lives in ∼ 10%, independently of the nuclear structure. Numerical computations were performed within the pn-QRPA, for 76 Ge, 128 T e and 130 T e nuclei. No one of the second-forbidden corrections modifies significantly the spectrum shapes. The total reduction in the calculated half lives varies from 6% up to 32%, and strongly depend on the nuclear interaction in the particle-particle S = 1, T = 0 channel. We conclude that the higher order effects in the weak Hamiltonian would hardly be observed in the two-neutrino double beta experiments.
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