Chemical properties of intermediate mass residue with isobaric yield ratio method in heavy-ion reaction

Background: Chemical properties of projectile residues are important in studying the symmetry energy using isobaric yield ratio (IYR) and isoscaling methods. Purpose: The correlation between chemical properties of intermediate mass residues and reaction systems is to be studied. It is hoped that the symmetry energy information can be extracted more precisely. Methods: In the framework of the grand-canonical ensemble theory, the △μ/T difference between two heave-ion reactions, which was labeled as △u21/T, was extracted by using isobaric yield ratio difference (IBD) method. Results: By comparing the △μ21/T among six different combinations ^48Ca+^9Be/^40Ca+^9Be, ^48Ca+^9Be/^58Ni+^9Be, ^64Ni+^9Be/^40Ca+^9Be, ^64Ni+^9Be/^58Ni+^9Be,^58Ni+^9Be/^40Ca+^9Be, ^48Ca+^9Be/^64Ni+^9Be, it was proved that △u/T depends on the reaction system. In different reactions, the values of A,tdT were not fixed. When the double neutron-to-proton ratios (N/Z)21=1. 17, △u21/T can be approximately a constant. Conclusion: Symmetry energy can be more reasonable in isoscaling and IBD methods, when double neutron-to-proton ratios (N/Z)21=1.17 between two similar reaction system.