- Physical Review Journals
All JournalsPhysics Magazine
Access Provided by Xinjiang University

Physical Review D

Export citation

Export citation

Choose format for download:

Download Citation
  • Access by Xinjiang University

Photoproduction of Electron-Positron Pairs at 2.3 and 5.6 GeV

J. Tenenbaum*, A. M. Eisner†, G. J. Feldman†, W. Lockeretz, F. M. Pipkin, and J. K. Randolph‡

  • Cyclotron Laboratory, Harvard University, Cambridge, Massachusetts 02138

  • *Present address: Stanford Linear Accelerator Center, Stanford, Calif.
  • †National Science Foundation Graduate Fellow.
  • ‡Present address: Randall Laboratory of Physics, University of Michigan, Ann Arbor, Mich.
PDF

Phys. Rev. D 2, 57 – Published 1 July, 1970

DOI: https://doi.org/10.1103/PhysRevD.2.57

Abstract

We have measured the photoproduction of electron-positron pairs from carbon using an improved version of the Harvard pair spectrometer. The bending magnet and two half-quadrupole magnets were retained. For each half-quadrupole, a tungsten collimator was added at the entrance, a portion of the lead obstacle was removed, and a defining counter was added at the midpoint. Faster counting electronics and an on-line computer were employed. Pairs were detected in an invariant-mass range of 97-445 MeV. The results are in agreement with the predictions of quantum electrodynamics and may be parametrized as R=(1.09±0.07)×[1+(31.6−41.2+31.2)×10−8QM2]. Here R is the ratio of experiment to theory, and QM2 is the electron-pair mass squared (GeV2c4). The errors include both statistical and systematic effects. In the course of this work, we have also derived an accurate approximation for the electron-pair cross section.

View figure in article

References (32)

  1. S. J. Brodsky, in International Symposium on Electron and Photon Interactions at High Energies, Liverpool, England, 1969, edited by D. W. Broben (Daresbury Nuclear Physics Laboratory, Daresbury, Lancashire, England, 1970), p. 3
  2. S. D. Drell, Ann. Phys. (N. Y.) 4, 75 (1958)
  3. W. C. Barber, B. Gittleman, G. K. O'Neill, and B. Richter, Phys. Rev. Letters 16, 1127 (1966)
  4. R. H. Siemann, W. W. Ash, K. Berkelman, D. L. Hartill, C. A. Lichtenstein, and R. M. Littauer, Phys. Rev. Letters 22, 421 (1969)
  5. A. D. Liberman, C. M. Hoffman, E. Engles, Jr., D. C. Imrie, P. G. Innocenti, R. Wilson, C. Zajde, W. A. Blanpied, D. G. Stairs, and D. Drickey, Phys. Rev. Letters 22, 663 (1969)
  6. B. Richter, Phys. Rev. Letters 1, 114 (1958)
  7. R. B. Blumenthal, D. C. Ehn, W. L. Faissler, P. M. Joseph, L. J. Lanzerotti, F. M. Pipkin, and D. G. Stairs, Phys. Rev. 144, 1199 (1966)
  8. P. L. Rothwell, R. C. Chase, D. R. Earles, M. Gettner, G. Glass, G. Lutz, E. von Goeler, and R. Weinstein, Phys. Rev. Letters 23, 1521 (1969)
  9. E. Eisenhandler, J. Feigenbaum, N. Mistry, P. Mostek, D. Rust, A. Silverman, C. Sinclair, and R. Talman, Phys. Rev. Letters 18, 425 (1967)
  10. J. G. Asbury, W. K. Bertram, U. Becker, P. Joos, M. Rohde, A. J. S. Smith, S. Friedlander, C. L. Jordan, and S. C. C. Ting, Phys. Rev. 161, 1344 (1967) H. Alvensleben, U. Becker, W. K. Bertram, M. Binkley, K. Cohen, C. L. Jordan, T. M. Knasel, R. Marshall, D. J. Quinn, M. Rohde, G. H. Sanders, and S. C. C. Ting, Phys. Rev. Letters 21, 1501 (1968)
  11. K. J. Cohen, S. Homma, D. Luckey, and L. S. Osborne, Phys. Rev. 173, 1339 (1968)
  12. P. J. Biggs, D. W. Braben, R. W. Clifft, E. Gabathuler, P. Kitching, and R. E. Rand, Phys. Rev. Letters 23, 927 (1969)
  13. S. Hayes, R. Imlay, P. M. Joseph, A. S. Keizer, J. Knowles, and P. C. Stein, Phys. Rev. Letters 22, 1134 (1969)
  14. J. D. Bjorken, S. D. Drell, and S. C. Frautschi, Phys. Rev. 112, 1409 (1958)
  15. J. K. Randolph, thesis, Harvard University, 1965 (unpublished)
  16. J. Fregeau, Phys. Rev. 104, 225 (1956)
  17. H. Crannell, Phys. Rev. 148, 1107 (1966)
  18. W. L. Faissler, F. M. Pipkin, and K. C. Stanfield, Phys. Rev. Letters 19, 1202 (1967)
  19. K. C. Stanfield, thesis, Harvard University, 1969 (unpublished)
  20. S. D. Drell and C. L. Schwartz, Phys. Rev. 112, 568 (1958)
  21. J. G. Rutherglen, in International Symposium on Electron and Photon Interactions at High Energies, Liverpool, England, 1969, edited by D. W. Braben (Daresbury Nuclear Physics Laboratory, Daresbury, Lancashire, England, 1970), p. 163
  22. H. A. Bethe and W. Heitler, Proc. Roy. Soc. (London) A146, 83 (1934)
  23. S. D. Drell and J. D. Walecka, Ann. Phys. (N. Y.) 28, 18 (1964)
  24. G. R. Henry, Phys. Rev. 153, 1649 (1967)
  25. B. Huld, Phys. Rev. 168, 1782 (1968)
  26. J. Tenenbaum, thesis, Harvard University, 1969 (unpublished)
  27. J. de Pagter and M. Fotino, Cambridge Electron Accelerator Report No. CEAL-1022, 1965 (unpublished) G. F. Dell and M. Fotino, Cambridge Electron Accelerator Report No. CEAL-1040, 1969 (unpublished)
  28. L. A. Law and J. Weinstein, Cambridge Electron Accelerator Report No. CEAL-1021, 1965 (unpublished)
  29. Y. S. Tsai and V. Whitis, Phys. Rev. 149, 1248 (1966)
  30. W. T. Scott, Rev. Mod. Phys. 35, 231 (1963)
  31. B. Rossi, High-Energy Particles (Prentice-Hall, Englewood Cliffs, N. J., 1952)
  32. N. M. Kroll, Nuovo Cimento 45, A65 (1966)

Outline

Information

Phys. Rev. D 2, 57– Published 1 July, 1970
  • Received 27 February 1970

© 1970 American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation