On the masses and modes of decay of heavy mesons produced by cosmic radiation

Mambillikalathil Govind Kumar Menon. 28 August 1928—22 November 2016

“…As noted earlier, Goku's collaboration with Friedlander resulted in several important results (9–11, 13–23): They showed that the production of K - by cosmic rays was suppressed significantly below that of K + (which was understood later by noting that the production of K - has a significantly higher threshold).They carried out improved measurements of the mass of Λ0, which yielded mnormalΛ=1114.6±0.22 MeV—very close to the modern value, 1115.60 MeV.A very rare event, −K + → e + + neutral particles, was discovered: e + was identified as such, by the large-angle scattering it suffered while emitting a bremsstrahlung gamma ray.In a major effort involving the study of ca 10 000 cosmic ray interactions, several events were found depicting the capture of K - mesons by nuclei, leading to the production of Λ0 and Σ0 hyperons. In the same paper (16), Goku coined the evocative phrase ‘associated production’ to describe their results, which implied the requirement that a strange particle be produced together with another particle of opposite strangeness in order to conserve strangeness.…”

“…Near the end of 1952, Michael Friedlander, with a Master's degree from Cape Town, South Africa, joined Powell's ‘fourth-floor group’ and became a close collaborator of Goku, and a series of about 15 joint papers emerged during the next four years (9–11, 13–23) pertaining to K mesons and hyperons. Before summarizing these findings, the scheme devised by Gell-Mann to theoretically understand some of these findings is introduced.…”