Chronology of Milestone Events in Particle Physics - CARLSON 1950
Chronology of Milestone Events in Particle Physics

CARLSON 1950

Carlson, A.G.; Hooper, J.E.; King, D.T.;
Nuclear Transmutations Produced by Cosmic-Ray Particles of Great Energy. - Part V. The Neutral Meson
Phil. Mag. 41 (1950) 701;

Summary
The spectrum of the -radiation in the atmosphere at 70,000 ft has been determined by observation on the scattering of pairs of fast electrons recorded in photographic emulsions exposed in high-flying balloons. The detailed form of the spectrum is consistent with the assumption that the -rays originate by the decay of neutral mesons. It is found that the mass of the neutral-mesons is 295 20 me, and that they are created in nuclear explosions with an "energy spectrum'' similar to that of the charged -particles. A method is described for determining the lifetime of the neutral mesons and their frequency of occurrence compared with charged -particles. The lifetime, o, is less than 5 x 10-14 sec. It may be possible to determine the lifetime, by observations of greater statistical weight, if it is longer than 2 x 10-14 sec. The ratio of the number of neutral mesons to charged mesons, produced in nuclear explosions of great energy, is equal to 0.45 0.10.

Accelerator COSM Detectors EMUL

Related references
More (earlier) information appears in
U. Camerini et al., Phil. Mag. 40 (1949) 1073;
See also
M. F. Kaplon, B. Peters, and H. L. Brandt, Helv. Phys. Acta 23 (1950) 24;
P. H. Fowler, Phil. Mag. 41 (1950) 169;
R. Bjorklund et al., Phys. Rev. 77 (1950) 213;
O. Piccioni, Phys. Rev. 77 (1950) 1;

Reactions
  unspec nucleus X p
  unspec nucleus o X p, cs
  o 2

Particles studied
  o ex, w, mass

Record comments
Confirmation of the existence of the o, first estimation of the o lifetime.
    
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