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  • Access by Xinjiang University

Fast Protons from the Capture of π Mesons in Photographic Emulsions

Frank L. Adelman

  • Radiation Laboratory, Department of Physics, University of California, Berkeley, California

Phys. Rev. 85, 249 – Published 15 January, 1952

DOI: https://doi.org/10.1103/PhysRev.85.249

Abstract

The spectrum of fast protons from 1631 π meson absorptions in Ilford G-5 and C-2 emulsions has been studied. It has been found that (16.1±1.8) percent of all π meson absorptions are accompanied by protons of energy greater than 20 Mev, and that (9.5±1.3) percent of all absorptions are accompanied by protons of energy greater than 30 Mev. The proton energies were estimated by grain counting in comparison with π mesons of known residual range. Allowance was made for the variation of grain density with position and depth in the emulsion. The energy spectrum is fairly flat from 30-70 Mev, but only three events were found above 70 Mev. Examination of stars from which the fast protons were emitted shows more prongs ejected opposite to the direction of the fast proton than are accounted for by evaporation from a recoiling nucleus. The energy spectrum favors the capture of the meson by a proton, with the recoil momentum taken by a small, variable number of nucleons. Furthermore, the evidence suggests that the low energy star prongs result from knock-on collisions of the primary nucleons with other nucleons inside the nucleus.

References (21)

  1. E. Clementel and G. Puppi, Nuovo cimento 6, 494 (1949)
  2. Y. Fujimoto and Y. Yamaguchi, Prog. Theor. Phys. 4, 468 (1949)
  3. D. Perkins, Phil. Mag. 40, 601 (1949)
  4. Menon, Muirhead, and Rochat, Phil. Mag. 41, 583 (1950)
  5. J. Heidmann and L. LePrince-Ringuet, Compt. rend. 226, 1716 (1948)
  6. R. Marshak, Echo Lake Symposium on Cosmic Radiation (1949)
  7. Fujimoto, Hayakawa, and Yamaguchi, Prog. Theor. Phys. 4, 576 (1949)
  8. S. Tamor, Phys. Rev. 77, 412 (1950)
  9. F. Adelman, Phys. Rev. 78, 86(A) (1950)
  10. W. Cheston and L. Goldfarb, Phys. Rev. 78, 683 (1950)
  11. Omitted endnote

  12. K. Bowker, Phys. Rev. 78, 87(A) (1950)
  13. J. Spence, private communication
  14. Omitted endnote

  15. Omitted endnote

  16. F. Adelman and S. Jones, Science 111, 226 (1950)
  17. Omitted endnote

  18. Fujimoto, Takayanagi, and Yamaguchi, Prog. Theor. Phys. 5, 498 (1950)
  19. S. Ruddlesden and A. Clark, Nature 164, 487 (1949)
  20. M. Goldberger, Phys. Rev. 74, 1269 (1948)
  21. Dr. H. York ([20]) J. Hadley and H. York, Phys. Rev. 80, 345 (1950)

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