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Direct Photon Production from Positive and Negative Pions and Protons at 200 GeV/c (NA3 Collaboration)

  • Flavio Costantini
Part of the NATO ASI Series book series (NSSB, volume 197)

Abstract

Direct photon production has been studied by the NA3 Collaboration at the CERN SPS using negative and positive beams at 200 GeV/c incident on an isoscalar Carbon target. The experiment, completed in 1985, published the first fixed target measurements of the asymmetry of prompt photon production by negative and positive pions. The experiment was sensitive to photons with 2.5 ≤ PT ≤ 6.0 GeV/c and C.M. rapidity — 0.4 ≤ Y ≤ 1.2.

NA3 final results on: a) direct photon production by π ± and protons b) charge asymmetry measurement on direct photon production from π and π + c) direct photon pair production by π ± and protons d) π° production measurements by π ±, K + and protons are recalled, commented on and compared to data recently published by other fixed target experiments.

Keywords

Differential Cross Section Photon Pair Direct Photon Photon Production Prompt Photon 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    P. Darriulat et al. Nucl. Phys. B110 (1976) 365ADSCrossRefGoogle Scholar
  2. For an exhaustive review see, for instance: T. Ferbel, W.R. Molzon “Direct photon production in high energy collisions ”. Rev. Mod. Phys. 56 (1984) 181ADSCrossRefGoogle Scholar
  3. 2.
    L. Bachman et al. CERN/SPSC/80-61 (WA70 Collaboration)Google Scholar
  4. A. Bamberger et al. CERN/SPSC/80-83 (NA24 Collaboration)Google Scholar
  5. R. Hagelberg et al. CERN/SPSC/80-106 (NA3 Collaboration)Google Scholar
  6. 3.
    J. Antille et al. CERN/SPSC/80-63 (UA6 Collaboration)Google Scholar
  7. 4.
    The conclusions of the working group on prompt photon physics, coordinated byGoogle Scholar
  8. F. Costantini, are in: “ Workshop on SPS fixed target physics in the years 1984–1989 ” Vol 2 CERN 83/02Google Scholar
  9. 5.
    See the Proceedings of this Workshop.Google Scholar
  10. 6.
    F. Costantini “Asymmetry measurements in direct photon production from negative and positive pions at 200 GeV/c”. Proceedings of XXII-th Int. Conference on H.E. Physics Leipzig (DDR) Vol 1 (1984) 281.MathSciNetGoogle Scholar
  11. 7.
    J. Badier et al. (NA3 Collaboration) “ Inclusive high PT π° production from π± and protons at 200 GeV/c”. Z. Phys. C 30 (1986) 45ADSCrossRefGoogle Scholar
  12. 8.
    J. Badier et al. (NA3 Collaboration) “ Direct photon production from pions and protons at 200 Gev/c”. Z. Phys. C 31 (1986) 341ADSCrossRefGoogle Scholar
  13. Y. Karyotakis Thesis Universite Paris Sud 1985 LPNHE Ecole Polytechnique.Google Scholar
  14. 9.
    J. Badier et al. (NA3 Collaboration) “ Direct photon pair production from pions and protons at 200 GeV/c ”. Phys. Lett. 164B (1985) 18Google Scholar
  15. 10.
    T. Akesson et al. Phys. Lett. 118B (1982) 178CrossRefGoogle Scholar
  16. 11.
    For a detailed discussion on this subject, see the review of ref. [1].Google Scholar
  17. 12.
    Four small beam chambers used in conjunction with a beam dipole measured the beam momentum with a precision AP/P = 0.8%. The momentum after the radiator was moreGoogle Scholar
  18. precisely measured by the NA3 S.C. dipole. A set of three movable dipoles placed in front of the spectrometer allowed the vertical deflection of electrons so leaving “isolated” the radiated photon. For more details see also the Thesis of ref. [8].Google Scholar
  19. 13.
    In reality a small (10%) correction to the pair energy measured by the spectrometer is given by the pair bremsstrahlung in the converter itself. The energy of bremsstrahlung photons is measured in the calorimeter.Google Scholar
  20. 14.
    The physics results of the WA70 Collaboration used for the comparison are from:Google Scholar
  21. M. Bonesini et al. High transverse momentum π° production by π and π+ on protons at 280 GeV/c “. CERN EP/87–164Google Scholar
  22. M. Bonesini et al. “ High transverse momentum prompt photon production by π and n+ on protons at 280 GeV/c ”. CERN EP/87–185Google Scholar
  23. M. Bonesini et al. “ Production of high transverse momentum prompt photons and neutral pions in proton-proton interactions at 280 GeV/c ”.Google Scholar
  24. Presented at the International Europhysics Conference on H.E. Physics Uppsala 1987Google Scholar
  25. 15.
    The physics results of the NA24 Collaboration used for the comparison are from:Google Scholar
  26. C. De Marzo et al. “ Measurement of direct photon production at large transverse momentum in πp, π+p and pp collisions at 300 GeV/c ”. Phys. Rev. D 36 (1987) 8ADSCrossRefGoogle Scholar
  27. C. De Marzo et al. “ Measurement of π° production at large transverse momentum in πp, π+p and pp collisions at 300 GeV/c ”. Phys. Rev. D 36 (1987) 16ADSCrossRefGoogle Scholar
  28. 16.
    P. Aurenche, R. Baier, A. Douiri, M. Fontannaz, D. Schiff. Phys. Lett. 140B (1984) 8Google Scholar
  29. P. Aurenche, R. Baier, A. Douiri, M. Fontannaz, D. Schiff. Nucl. Phys. B286 (1987) 509ADSCrossRefGoogle Scholar
  30. 17.
    P. Aurenche et al., preprint LPTHE Orsay 85/20Google Scholar

Copyright information

© Plenum Press, New York 1988

Authors and Affiliations

  • Flavio Costantini
    • 1
    • 2
  1. 1.Dipartimento di FisicaUniversita’ di PisaItaly
  2. 2.Sezione di PisaINFNItaly

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