Inelastic Final-State Interactions:K−Absorption in Deuterium

In a reaction from which several strongly interacting particles emerge it is often possible to isolate the effects of forces between two of the outgoing particles. There are many cases in which this final-state interaction can produce inelastic reactions. The formalism that describes this situation is developed here, and the reaction $K^{-}+d\to \pi +\Sigma +N\to \pi +\Lambda +N^{\prime }$ is studied in detail as an example. It is found that large $\frac{\Lambda }{\Sigma }$ branching ratios can result and can be used to restrict the $\Sigma -N$ and $K-N$ interaction parameters. The gross features of the spectrum can be understood using a simple model. It does not seem possible to determine the parities of the strange particles from the momentum spectra. When the inelastic reaction in the final state is exothermic, as in the example, high partial waves may contribute.