Thermally-induced expansion in the 8 GeV/c ${\pi }^{-}$ + ${}^{197}$Au reaction

Abstract

Fragment kinetic energy spectra for reactions induced by 8.0 GeV/c ${\pi }^{-}$ beams incident on a ${}^{197}$Au target have been analyzed in order to deduce the possible existence and influence of thermal expansion. The average fragment kinetic energies are observed to increase systematically with fragment charge but are nearly independent of excitation energy. Comparison of the data with statistical multifragmentation models indicates the onset of extra collective thermal expansion near an excitation energy of E*/A $\approx$ 5 MeV. However, this effect is weak relative to the radial expansion observed in heavy-ion-induced reactions, consistent with the interpretation that the latter expansion may be driven primarily by dynamical effects such as compression/decompression.

12 pages including 4 postscript figures

References in corpus (7)

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Cited by in corpus (9)

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• Light-Ion-Induced Multifragmentation: The ISiS Project
• Statistical description of nuclear break-up
• The Nuclear Liquid-Gas Phase Transition: Q.E.D
• Tracking the phase-transition energy in disassembly of hot nuclei
• Caloric curve of 8 GeV/c negative pion and antiproton + Au reactions
• Effects of in-medium cross-sections and optical potential on thermal-source formation in p+197Au reactions at 6.2-14.6 GeV/c
• Comment on Breakup Densities of Hot Nuclei