Backward yields of pions, protons, and deuterons in relativistic 28Si+Pb collisions at 14.6 A GeV/c

J. Barrette, R. Bellwied, S. Bennett, P. Braun-Munzinger, W. E. Cleland, T. M. Cormier, G. David, J. Dee, G. E. Diebold, O. Dietzsch, J. V. Germani, S. Gilbert, S. V. Greene, J. R. Hall, T. K. Hemmick, N. Herrmann, B. Hong, K. Jayananda, D. Kraus, B. Shiva KumarR. Lacasse, Q. Li, D. Lissauer, W. J. Llope, T. W. Ludlam, A. Lukaszew, R. Majka, S. K. Mark, R. Matheus, S. McCorkle, J. T. Mitchell, M. Muthuswamy, E. O'Brien, S. Panitkin, C. Pruneau, M. N. Rao, M. Rosati, F. Rotondo, N. C. Da Silva, U. Sonnadara, J. Stachel, H. Takai, E. M. Takagui, T. G. Throwe, S. Voloshin, G. Wang, D. Wolfe, C. L. Woody, N. Xu, Y. Zhang, Z. Zhang, C. Zou

Research output: Contribution to journalArticlepeer-review


The production of pions, protons and deuterons is studied at a laboratory angle of 144°. In 28Si+Pb collisions at 14.6 GeV/c per nucleon. The centrality dependence of the pion yields is studied over the full impact parameter range using a zero degree calorimeter. The results are compared with the hadronic cascade model RQMD. These calculations are generally in agreement with the experimental results. According to these calculations, the pion yield in our acceptance is completely dominated by Δ-decay at freeze-out. Our measurements thus support the importance of baryon resonance production as one of the central features of relativistic heavy ion collisions at AGS energies. Although the strength of the pion spectrum is adequately described for kinetic energies above 50 MeV, an additional very soft component is observed in the pion spectra which is not predicted by RQMD. This very soft component accounts for a significant fraction of the total pion yield in this rapidity range but remains unexplained.

Original languageEnglish
Pages (from-to)391-403
Number of pages13
JournalNuclear Physics A
Issue number3
Publication statusPublished - 1997 Sept 1
Externally publishedYes

Bibliographical note

Funding Information:
We thank the AGS and Tandem staff and, in particular, Dr. H. Brown and W. Mc-Gahern for their excellent support. We also thank R. Hutter for technical support. This work was supported by DoE, the NSE the NSERC (Canada), and the CNPq (Brazil).


  • AGS Si+Pb
  • Backward hemisphere
  • Relativistic heavy-ion collision

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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