Nonmesonic weak decay of light hypernuclei with coherent $\hat{I}\pounds$ mixing

Abstract

Nonmesonic weak decays of the A=4, and 5 hypernuclei are studied. The short range parts of the hyperon-nucleon weak interactions are described by the direct quark (DQ) weak transition potential, while the longer range interactions are given by the $\ddot{I}€$ and $K$ meson exchange processes. Virtual $\hat{I}\pounds$ mixings of the coherent type are found to give significant effects on the decay rates of ${}_{\hat{I}}^4›\mathrm{He}$. A large violation of the $\hat{I}”I=1/2$ rule is predicted in the J=0 transition amplitudes.

17 pages, 2 figures