中文摘要：

基于LHCb，Tevatron以及DO实验组关于中性Bs介子混合的最新实验结果，Г12s中有可能存在大的新物理贡献，本文在代非普适Z’模型下对Bs-Bs混合进行了研究．假定Z’玻色子不仅对非对角矩阵元M12s有贡献，还考虑了由树图交换Z’玻色子所导致的b→scc算符对非对角矩阵元Г12s的贡献．结果表明：在△Ms，φs和豆Bd→J/φKs的间接CP不对称这些物理可观测量的联合限制下，实验值afss得不到解释．因此，在对非普适Z’模型假定下，不能同时对所有中性Bs介子混合观测量给出解释．伴随着LHCb以及未来的超级B工厂的运行，尤其是对CP不对称afss的测量，期望这一问题将得到解答．

英文摘要：

Motivated by recent measurements of the neutral Bs-meson mixing, obtained by LHCb group and the Tevatron, and the possibility to have sizable NP effects in Г12s, we revisit the Bs- Bs mixing in a family non-universal Z＇ model. We assume that the Z＇ boson contributes to the off-diagonal elementM12s and also to the off-diagonal element Г12S via tree-level Z＇-induced b → scc operators. We find that, with the constraints from △Msφs and the indirect CP asymmetry in Bd→J/φKs imposed, the present measured 1σ experimental ranges for afss could not be reproduced. Thus, such a specific model could not simultaneously explain the present data on Bs mixing. It is expected that with the operation of the LHCb group and the future super B experiments, more accurate measurements, especially of the flavour-specific CP asymmetries, could shed light on the issue.