Strong Initial- and Final-State Interactions in Nonmesonic Hyper-nuclear Decays and in Parity-ViolatingN+N→N+NReactions

A distorted-wave Born calculation is used to show that the strong initial- and final-state interactions in the nonmesonic hypernuclear decays, $\Lambda +N\to N+N$, are of major importance, greatly suppressing certain transitions, and suggest the dominance of one-pion exchange in the explanation of hypernuclear decay rates. Weak exchange of heavier mesons is also suppressed by the strong interactions both in $\Lambda +N\to N+N-$ badly breaking any $\mathrm{SU}\left(3\right)\mathrm{}$ symmetry of the reactions—and in the parity-violating $N+N\to N+N$. It is shown that the decay rate of heavy hypernuclei provides a measure of the $\Lambda -N$ correlation function at short distances in nuclear matter and should depend significantly on the existence of a hard core in the $\Lambda -N$ strong interaction.