Chronology of Milestone Events in Particle Physics - LEIGHTON 1949
Chronology of Milestone Events in Particle Physics


Leighton, R.B.; Anderson, C.D.; Seriff, A.J.;
The Energy Spectrum of the Decay Particles and the Mass and Spin of the Mesotron
Phys. Rev. 75 (1949) 1432; Phys. Rev. 76 (1949) 159;

Energy values determined from measurements of 75 cloud-chamber tracks of decay particles of cosmic-ray mesotrons at sea level, in a magnetic field of 7250 gauss, are here reported. The observed spectrum extends from 9 MeV to 55 MeV with an apparently continuous distribution of intermediate energy values and a mean energy of 34 MeV. The shape of the spectrum and the value of its upper limit are strong evidence that the mesotron has half-integral spin. The value of the observed upper limit of the energy spectrum corresponds to a mass value of the mesotron equal to 217 4 electron masses.

Accelerator COSM Detectors CLOUD

Related references
More (earlier) information appears in
R. B. Leighton, C. D. Anderson, and A. J. Seriff, Phys. Rev. 75 (1949) 1432;
See also
J. Tiomno and J. A. Wheeler, Rev. of Mod. Phys. 21 (1949) 144;
S. H. Neddermeyer and C. D. Anderson, Rev. of Mod. Phys. 11 (1939) 201;
Analyse data from
E. C. Fowler, R. L. Cool, and J. C. Street, Phys. Rev. 74 (1948) 101;
J. L. Zar, J. Hershkowitz, and E. Berezin, Phys. Rev. 74 (1948) 111;
J. Steinberger, Phys. Rev. 74 (1948) 500;
E. P. Hincks and B. Pontecorvo, Phys. Rev. 73 (1948) 257;
E. P. Hincks and B. Pontecorvo, Phys. Rev. 74 (1948) 697;
E. P. Hincks and B. Pontecorvo, Phys. Rev. 75 (1949) 698;
M. H. Shamos and A. Russek, Phys. Rev. 74 (1948) 1545;
K. C. Wang and S. B. Jones, Phys. Rev. 74 (1948) 1547;
R. H. Brown et al., Nature 163 (1949) 47;
C. T. R. Wilson and J. G. Wilson, Proc. Roy. Soc. A148 (1935) 523;
J. C. Fletcher and H. K. Forster, Phys. Rev. 75 (1949) 204;
A. S. Bishop, Phys. Rev. 75 (1949) 1468A;
O. Piccioni, Phys. Rev. 74 (1948) 1754;
C. D. Anderson, R. V. Adams, P. E. Lloyd, and R. R. Rau, Phys. Rev. 72 (1947) 724;
R. W. Thompson, Phys. Rev. 75 (1949) 1279;
R. W. Thompson, Phys. Rev. 74 (1948) 490;
R. D. Sard and E. J. Althaus, Phys. Rev. 75 (1949) 1251;

  e 2neutral p

Particles studied
  mass, qn
  + mass, qn

Record comments
Confirmation of the continuous energy distribution of the e in the decay e X. Muon spin = 1/2.
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