Sub-barrier fusion cross sections: role of Pauli blocking and isospin asymmetry*

Abstract Heavy-ion fusion reactions are relevant to numerous important issues in the stellar environment as well as in the synthesis of new nuclides and superheavy elements. In this study, the role of Pauli blocking and the isospin effect in sub-barrier fusion reactions is investigated using the well established coupled-channel method. An isospin-dependent Pauli blocking potential is proposed to better address the deep sub-barrier fusion hindrance problem. We find that the Pauli blocking effect manifests itself strongly for isospin symmetric targets and is reduced for targets with large isospin asymmetries. The agreement between experimental and theoretical fusion cross sections is improved for both the 12 C-target and 16 O-target systems.