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The branching ratios for the primary interactions of K−-mesons at rest with carbon nuclei have been determined by means of a heavy-liquid bubble chamber filled with a mixture of hydrocarbons. The results are compared with those obtained in other absorbing media, and the question of the existence of a halo of neutrons at the surface of heavy nuclei is discussed in the light of these new results.

Decay branching ratios of the\({}_\Lambda ^4 He\)c hypernucleus have been measured using a sample of hypernuclei produced in the interactions at rest of K−-mesons in a helium bubble chamber. The observation of 6 π+-mesonic decays leads to a value of 0.043±0.017 for the π+-mesonic/π−-mesonic decay branching ratio. No examples of the charged two-body nonmesonic decays of the hypernucleus were observed.

In a sample of approximately 11 000 hypernuclei obtained from K−-meson captures at rest in nuclear emulsion, eleven examples of the π+-mesonic decay of hypernuclei have been observed. From the ten which are attributed to the decay of4HeΛ, a value of (9±3)% is obtained forR, the ratio of π+ to π− mesonic decays for this hypernucleus. This result is larger than both that previously found experimentally and that predicted theoretically.

Results are presented on the\(B_\Lambda \) values of hypernuclei in the mass rangeA=3 toA=12 obtained from a sample of 595 uniquely identified π−-mesonic decays. The problems of what constitute adequate selection criteria for the unique identification of an event are discussed. The disagreement between the\(B_\Lambda \) values obtained from different decay modes of\({}^4B_\Lambda \) indicates a possible error in the range-energy relationship.