Measurement of pion enhancement at low transverse momentum and of the Δ resonance abundance in Si-nucleus collisions at AGS energy

J. Barrette, R. Bellwied, 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, Byungsik Hong, K. Jayananda, D. Kraus, B. S. Kumar, R. LacasseD. Lissauer, W. J. Llope, T. W. Ludlam, S. McCorkle, R. Majka, S. K. Mark, J. T. Mitchell, M. Muthuswamy, E. O'Brien, C. Pruneau, M. N. Rao, F. Rotondo, N. C. DaSilva, U. Sonnadara, J. Stachel, H. Takai, E. M. Takagui, T. G. Throwe, G. Wang, D. Wolfe, C. L. Woody, N. Xu, Y. Zhang, Z. Zhang, C. Zou

Research output: Contribution to journalArticle

50 Citations (Scopus)


We present measurements of pion transverse momentum (pt) spectra in central Si-nucleus collisions in the rapidity range 2.0 < < 5.0 for pt down to and including pt = 0. The data exhibit an enhanced pion yield at low pt compared to what is expected for a purely thermal spectral shape. This enhancement is used to determine the Δ resonance abundance at freeze-out. The results are consistent with a direct measurement of the Δ resonance yield by reconstruction of proton-pion pairs and imply a temperature of the system at freeze-out close to 140 MeV.

Original languageEnglish
Pages (from-to)93-98
Number of pages6
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number1-3
Publication statusPublished - 1995 Dec 1
Externally publishedYes


ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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