Violation of the ΔI=1/2 rule in the nonmesonic weak decay of hypernuclei

Violations of the ΔI=1/2 rule are investigated in the nonmesonic weak hypernuclear decay using a weak ΛN→NN transition potential based on meson exchange. While the weak ΔI=3/2 couplings of baryons to pseudoscalar mesons are known to be very small, the analogous couplings of baryons to vector mesons, evaluated using the factorization approximation, are found to produce potentially significant changes in the predictions for hypernuclear decay observables in the case of Λ12C.