Caloric curve of 8 GeV/cπ-, p̄+ 197Au reactions

Abstract

The relationship between nuclear temperature and excitation energy of hot nuclei formed by 8 GeV/c negative pion and antiproton beams incident on 197Au has been investigated with the ISiS 4 π detector array at the BNL AGS accelerator. The double-isotope-ratio technique was used to calculate the temperature of the hot system. The two thermometers used, (p/d-3He/4He) and (d/t-3He/4He), are in agreement below E*/A ∼8 MeV when corrected for secondary decay. Caloric curves derived from successive segments of the H and He kinetic energy spectra show a systematic decrease in temperature as the kinetic energy bin decreases, consistent with "cooling curve" behavior. When extrapolated to the evaporative-peak region, these results provide good agreement with caloric curves measured for similar systems. The caloric curves from this experiment are also compared with the predictions from the SMM multifragmentation model.