Entrance-channel Mass-asymmetry Dependence of Compound-nucleus Formation Time in Light Heavy-ion Reactions

Abstract

The entrance-channel mass-asymmetry dependence of the compound nucleus formation time in light heavy-ion reactions has been investigated within the framework of semiclassical dissipative collision models. the model calculations have been succesfully applied to the formation of the ${}^{38}$Ar compound nucleus as populated via the ${}^9$Be+${}^{29}$Si, ${}^{11}$B+${}^{27}$Al, ${}^{12}$C+${}^{26}$Mg and ${}^{19}$F+${}^{19}$F entrance channels. The shape evolution of several other light composite systems appears to be consistent with the so-called "Fusion Inhibition Factor" which has been experimentally observed. As found previously in more massive systems for the fusion-evaporation process, the entrance-channel mass-asymmetry degree of freedom appears to determine the competition between the different mechanisms as well as the time scales involved.

12 pages, 3 Figures available upon request, Submitted at Phys. Rev. C