LVI. Mechanism of π-meson disintegrations

Abstract

The present paper describes observations made on the disintegration stars produced by nuclear capture of slow negative mesons, in nuclear plates exposed to cosmic radiation. These measurements are in confirmation of the hypotheses previously put forward (Heidmann and Leprince-Ringuet 1948, Perkins 1948) to account for the conversion of the mesonrest-energy into nuclear excitation energy, namely that this mass energy is transferred into kinetic energy of one or two nucleons, which subsequently excite the nucleus in their passage through it. Previous measurements of the mass of the star-producing mesons (Lattimore 1948, Goldschmitd-Clermont, King, Muirhead, and Ritson 1948) and evidence from grain-counts described below, indicate that they can all, or nearly all, be identified with the negative 7r-mesons of mass 285 produced in the Berkeley cyclotron.