Statistical analysis of experimental multifragmentation events in $^{64}$Zn + $^{112}$Sn at 40 MeV/nucleon.

A statistical multifragmentation model (SMM) is applied to the experimentally observed multifragmentation events in an intermediate heavy ion reaction.Using the temperature and symmetry energy extracted from the isobaric yield ratio (IYR) method based on the Modified Fisher Model (MFM), SMM is applied to the reaction $^{64}$Zn + $^{112}$Sn at 40 MeV/nucleon. The experimental isotope distribution and mass distribution of the primary reconstructed fragments are compared without afterburner and they are well reproduced. The extracted temperature $T$ and symmetry energy coefficient $a_{sym}$ from SMM simulated events, using the IYR method, are also consistent with those from the experiment. These results strongly suggest that in the multifragmentation process there is a freezeout volume, in which the thermal and chemical equilibrium is established before or at the time of the intermediate-mass fragments emission.