Optical model potentials for He6+Zn64 from Cu63(Li7,He6)Zn64 reactions

Abstract

Angular distributions of the transfer reaction $^{63}\mathrm{Cu}(^{7}\mathrm{Li},^{6}\mathrm{He})^{64}\mathrm{Zn}$ were measured at ${E}_{\mathrm{lab}}(^{7}\mathrm{Li})=12.67$, 15.21, 16.33, 23.30, 27.30, and 30.96 MeV. With the interaction potentials of the entrance channel $^{7}\mathrm{Li}+^{63}\mathrm{Cu}$ obtained from elastic scattering data as input, the optical potentials of the halo nuclear system $^{6}\mathrm{He}+^{64}\mathrm{Zn}$ in the exit channel were extracted by fitting the experimental data with the distorted-wave Born approximation (DWBA) and coupled reaction channels (CRC) methods, respectively. The results show that the threshold anomaly presents in the weakly bound system of $^{7}\mathrm{Li}+^{63}\mathrm{Cu}$ and the dispersion relation can be adopted to describe the connection between the real and imaginary potentials, while both the real and imaginary potentials nearly keep constant within the researched energy region for the halo system of $^{6}\mathrm{He}+^{64}\mathrm{Zn}$. Moreover, calculations by the potentials extracted from the CRC method can reproduce the experimental elastic scattering of the $^{6}\mathrm{He}+^{64}\mathrm{Zn}$ system rather well, but those by the potentials from the DWBA method cannot, where the couplings between $^{7}\mathrm{Li}$ and $^{6}\mathrm{He}$ are absent. This work verifies the validity of the transfer method in the medium-mass target region and lays a solid foundation for the further study of optical potentials for exotic nuclear systems.