The nonmesonic decay of the hypertriton is calculated based on a hypertriton wave function and 3N scattering states, which are rigorous solutions of three-body Faddeev equations using realistic NN and hyperon-nucleon interactions. The pion exchange together with heavier meson exchanges for the {Lambda}N{r_arrow}NN transition is considered. The total nonmesonic decay rate is found to be 0.5{percent} of the free {Lambda} decay rate. Integrated as well as differential decay rates are given. The p- and n-induced decays are discussed thoroughly and it is shown that the corresponding total rates cannot be measured individually.

The nonmesonic weak decay of 3 Λ H is evaluated microscopically in the pion exchange model. The correlated three-body wave function of the hypertriton is approximated by a bound Λ-deuteron system obtained by averaging the YN interaction over the deuteron wave function. The relevant matrix elements are calculated in momentum space. The resulting decay rate is 4.9% of the free Λ decay rate.