Λ0-Fragment Decay in a Cloud Chamber

Abstract

The decay in flight of a heavy nuclear fragment is described. The event is most reasonably interpreted as the decay of a ${\ensuremath{\Lambda}}^{0}$ particle bound to a ${\mathrm{He}}^{3}$ nucleus, and is similar to examples previously observed in nuclear emulsions. The lifetime of the excited fragment in this single example is 5.4\ifmmode\pm\else\textpm\fi{}0.6\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}10}$ sec, and the binding energy of the ${\ensuremath{\Lambda}}^{0}$ to ${\mathrm{He}}^{3}$ is probably less than 2 Mev.