Article révisé par les pairs
Résumé : In this experiment the relative rates of production of charged Σ hyperons by the capture of K- mesons on neutrons and protons in the heavy (silver and bromine) and the light emulsion nuclei (carbon, nitrogen and oxygen) have been measured. From these results it is concluded that there is a large neutron excess present in the outermost regions of heavy nuclei. © 1967.