Re-examination of Finite-Size Effects in Isobaric Yield Ratios Using a Statistical Abrasion-Ablation Model

The "finite-size" effects in the isobaric yield ratio (IYR), which are shown in the standard grand-canonical and canonical statistical ensembles (SGC/CSE) method, are claimed to prevent the actual values of physical parameters from being obtained. The conclusion of SGC/CSE may be questionable for neutron-rich nucleus-induced reactions. To investigate whether the IYR has finite-size effects, we re-examine the IYR for the mirror nuclei [IYR(m)] using a modified statistical abrasion-ablation (SAA) model. It is found that when the projectile is not so neutron-rich, the IYR(m) depends on the isospin of the projectile, but size dependence can not be excluded. In reactions induced by the very neutron-rich projectiles, contrary results to those of the SGC/CSE models are obtained, i.e., the dependence of the IYR(m) on the size and the isospin of the projectile is weakened and disappears in both the SAA and experimental results.