The excitation function for quasielastic scattering of the weakly bound projectile ${}^6\mathrm{Li}$ on a ${}^{159}\mathrm{Tb}$ target, at large backward angle, has been measured at energies around the Coulomb barrier. The corresponding quasielastic barrier distribution has been extracted from the experimental cross sections, both including and excluding the $\alpha$ particles produced in the reaction. The quasielastic scattering cross sections, excluding the $\alpha$ particles, have been analyzed in the framework of coupled channels calculations. The centroid of the quasielastic barrier distribution, including the $\alpha$ particles, is found to shift towards higher energy relative to the centroid of the fusion barrier distribution for the system. This has been attributed to the low $\alpha$-breakup threshold of the nucleus ${}^6\mathrm{Li}$.

中文翻译：

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弱束缚射弹Li6onTb159的准弹性后向散射和势垒分布

弱束缚弹体准弹性散射的激发函数 ${}^6李$ 在一个 ${}^{159}\mathrm{结核病}$已在库仑势垒周围的能量处测量了大后角的目标。从实验截面中提取了相应的准弹性势垒分布，包括和不包括$\alpha$反应中产生的颗粒。准弹性散射截面，不包括$\alpha$粒子，已在耦合通道计算的框架内进行了分析。准弹性势垒分布的质心，包括$\alpha$发现粒子相对于系统的聚变势垒分布的质心向更高的能量转移。这归因于低$\alpha$- 细胞核分裂阈值 ${}^6李$.