Testing binomial reducibility and thermal scaling in hadron-induced multifragmentation

A binomial reducibility and thermal scaling analysis is performed on well-chacracterized thermal-like sources formed in 8 GeV/c π^- + ¹⁹⁷Au reactions. The fragment probability distributions are shown to be binomial when plotted as a function of the measured excitation energy E* and the binomial elementary probability p is shown to follow the expected Boltzmann factor: ln(p)∝exp(-B/√E*/A). Binomial reducibility and thermal scaling are explored also using global variables other than E*, and the effect of source size on the binomial parameter p and m is shown. Finally, the extracted probability p is found to be correlated with the experimentally deduced fragment emission time up to about 6A MeV of excitation energy, hinting at a possible transition in decay mechanism above that excitation energy.