Deformed shell effects in 48Ca+249Bk quasifission fragments
Abstract
Background: Quasifission is the main reaction channel hindering the formation of superheavy nuclei (SHN). Its understanding will help to optimize entrance channels for SHN studies. Quasifission also provides a probe to understand the influence of shell effects in the formation of the fragments. Purpose: Investigate the role of shell effects in quasifission and their interplay with the orientation of the deformed target in the entrance channel. Methods: 48Ca+249Bk collisions are studied with the time-dependent Hartree-Fock approach for a range of angular momenta and orientations. Results: Unlike similar reactions with a 238U target, no significant shell effects which could be attributed to 208Pb "doubly-magic" nucleus are found. However, the octupole deformed shell gap at N=56 seems to strongly influence quasifission in the most central collisions. Conclusions: Shell effects similar to those observed in fission affect the formation of quasifission fragments. Mass-angle correlations could be used to experimentally isolate the fragments influenced by N=56 octupole shell gaps.