Recent developments in heavy-ion fusion reactions around the Coulomb barrier

¹ Department of Physics, Tohoku University, Sendai 980-8578, Japan
² Research Center for Electron Photon Science, Tohoku University, 1-2-1 Mikamine, Sendai 982-0826, Japan
³ National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka Tokyo 181-8588, Japan
⁴ Institut de Physique Nucléaire, UMR 8608, CNRS-IN2P3 et Université de Paris Sud, 91406 Orsay Cedex, France
⁵ School of Physical Science and Technology, Southwest University, Chongqing 400715, China
⁶ Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27516-3255, USA

Published online: 21 June 2016

Abstract

The nuclear fusion is a reaction to form a compound nucleus. It plays an important role in several circumstances in nuclear physics as well as in nuclear astrophysics, such as synthesis of superheavy elements and nucleosynthesis in stars. Here we discuss two recent theoretical developments in heavy-ion fusion reactions at energies around the Coulomb barrier. The first topic is a generalization of the Wong formula for fusion cross sections in a single-channel problem. By introducing an energy dependence to the barrier parameters, we show that the generalized formula leads to results practically indistinguishable from a full quantal calculation, even for light symmetric systems such as ¹²C+¹²C, for which fusion cross sections show an oscillatory behavior. We then discuss a semi-microscopic modeling of heavy-ion fusion reactions, which combine the coupled-channels approach to the state-of-the-art nuclear structure calculations for low-lying collective motions. We apply this method to subbarrier fusion reactions of ⁵⁸Ni+⁵⁸Ni and ⁴⁰Ca+⁵⁸Ni systems, and discuss the role of anharmonicity of the low-lying vibrational motions.