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Neutral Pion Production in Nucleus-Nucleus Collisions at 158 and 200 GeV/Nucleon

  • F. Plasil

Abstract

Two years ago, at the 12th Winter Workshop on Nuclear Dynamics held here in Snowbird, I presented WA80 limits on direct photon production in 200-GeV 32S+Au collisions.1 It was found that the results were consistent (within 1 σ) with the absence of an excess of photons over those that can be accounted for by the two-photon decay branches of π0 and η mesons and by the small photon contributions from other radiative decays. We are in the process of finalizing our direct-photon production results from collisions of lead nuclei at 158 GeV/nucleon. I will briefly discuss the status of the analysis and give some preliminary results at the end of this talk. However, most of this presentation is concerned with a very different aspect of our photon measurements: distributions of neutral pions. In contrast to direct photons which probe initial collision conditions, hadrons, such as neutral pions, interact strongly and decouple late in the reaction evolution and, thus, provide us with information concerning the system at freeze out. Transverse momentum spectra at low and intermediate PT relate to ther-modynamic and hydrodynamic descriptions of the hot, dense systems. In addition, the high-pT region reflects the hard-scattering regime and may help us understand initial-state particle production by forming a bridge to proton-proton and proton-nucleus results. It follows that it is essential that the π0 measurements cover a large pT range.

Keywords

Quark Matter Neutral Pion Direct Photon Local Slope Peripheral Collision 
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.
    F. Plasil in “Advances in Nuclear Dynamics 2,” Proc. 12th Winter Workshop on Nuclear Dynamics, Snowbird, Utah, 1996, Plenum Press, New York (1996), p. 365.Google Scholar
  2. 2.
    R. Albrecht et al., WA80 Collaboration, submitted to European Physical Journal C.Google Scholar
  3. 3.
    B. Wyslouch et al., WA98 Collaboration, in “Quark Matter’ 97,” Proc. Thirteenth Int. Conf. on Ultra-relativistic Nucleus-Nucleus Collisions, Tsukuba, Japan, 1997, to be published.Google Scholar
  4. 4.
    T. Peitzmann, WA98 Collaboration, in “Quark Matter’ 97,” Proc. Thirteenth Int. Conf. on Ultra-relativistic Nucleus-Nucleus Collisions, Tsukuba, Japan, 1997, to be published.Google Scholar
  5. 5.
    B. Alper et al., Nucl. Phys. B100:237 (1975).ADSCrossRefGoogle Scholar
  6. 6.
    C. DeMarzo et al., NA24 Collaboration, Phys. Rev. D 36:16 (1987).ADSCrossRefGoogle Scholar
  7. 7.
    K. Geiger, Phys. Rev. D 46:4965 (1992); 46: 4986 (1992).ADSCrossRefGoogle Scholar
  8. 8.
    K. Werner, Phys. Rep. 232:87 (1993).ADSCrossRefGoogle Scholar
  9. 9.
    B. Andersson, G. Gustafson, and H. Pi, Z. Phys. C 57:485 (1993).ADSCrossRefGoogle Scholar
  10. 10.
    K. S. Lee and U. Heinz, Z. Phys. C 43:425 (1989).ADSCrossRefGoogle Scholar
  11. 11.
    E. Schnedermann et al., Phys. Rev. C 48:2462 (1993).ADSCrossRefGoogle Scholar
  12. 12.
    E. Schnedermann, Phys. Rev. C 50:1675 (1994).ADSCrossRefGoogle Scholar
  13. 13.
    U. A. Wiedemann and U. Heinz, Phys. Rev. C 56:3265 (1997).ADSCrossRefGoogle Scholar
  14. 14.
    J. R. Nix et al. in proceedings of this conference.Google Scholar
  15. 15.
    R. Albrecht et al., Phys. Rev. Lett. 76:3506 (1996).ADSCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1998

Authors and Affiliations

  • F. Plasil
    • 1
  1. 1.Physics DivisionOak Ridge National LaboratoryOak RidgeUSA

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