"On the Disintegration of Negative Mesons", in Physical Review

CONVERSI, M. E. Pancini, and O. Piccioni, "On the Disintegration of Negative Mesons", in Physical Review, vol 71 no. 3, February 1, 1947, pp 209 in the issue. Original wrappers. GOOD copy, only.[++] "Evidence that the muon is not a strong action mediator"--Ezhela, Particle Physics, One Hundred Years of Discoveries. See also: Cahn and Goldhaber, "The Experimental Foundation of Particle Physics", 1989, where the article is reproduced in full on pp 37-8. This is a fundamental paper in developing the "Two-Meson" hypothesis. [++]"There was a precursor of that and a very exciting and, I would say, epoch-making paper that came out, at the beginning of 47. It was on work done during the war but published at that time. And that was the paper by Conversi, Pancini and Piccioni, [the paper offered here] wherein they reported that the negative cosmic ray mesons were not all absorbed in carbon, which they should have been, but there was substantial decay. A large percentage - like a half - decayed. The people who first realized how startling this development was, were Fermi, Teller and Weisskopf. They wrote a paper just before the Shelter Island Conference that pointed out that the Italian experiment implied a factor of something like 10 discrepancy between the strength of the meson-nucleon interaction that one expected and the strength that was implied by the observations of the Italian group."--Robert Marshak, oral history project interview at the AIP online [++] Also see: R. E. Marshak and H. A. Bethe, "On the Two-Meson Hypothesis", Phys. Rev. 72, 506 15 September 1947. …