Experimental studies of the competition between fusion and quasifission in the formation of heavy and superheavy nuclei

Abstract

Quasifission competes with fusion, and can suppress the cross sections for formation of heavy elements by orders of magnitude. Its understanding is important both to map out opportunities to synthesise superheavy elements and isotopes, and to understand the non-equilibrium dynamics that controls heavy ion reactions. A review of experimental studies of quasifission is presented, summarising significant insights obtained experimentally over the last 40 years. Possible origins for conflicting results are discussed, to try to identify and/or resolve outstanding discrepancies between different investigations at different times. Work in the last 10 years has highlighted the strong influence of the nuclear structure of the two colliding nuclei on the competition between quasifission and fusion. New approaches to separate the yields of quasifission and fusion–fission are discussed.