中文摘要：

采用微扰QCD方法,考虑树图算符和企鹅图算符对Υ（nS）→BcDs,BcDd弱衰变过程中发射图和湮灭图两种拓扑振幅（其中n=1,2,3）的贡献,结果表明Υ（nS）→BcDs,BcDd的分支比分别可以达到10-10和10-11量级.这些过程有可能在未来的高能物理实验中被观测到.

英文摘要：

TheΥ（nS）→BcDs,BcDd weak decays are studied with the perturbative QCD approach,considering the contributions of both tree and penguin operators to both emission and annihilation topologies where n=1,2,3.It is found that branching ratios forΥ（nS）→BcDsand BcDddecays can reach up to 10.-10 and 10.-11,respectively,which might be measurable in the future high energy experiments.