标题： 标准模型和MSSM对电弱精密数据的全局拟合 显示英文标题

标题： Global Fits of the SM and MSSM to Electroweak Precision Data

摘要： 一个包括所有辐射修正的程序，其在与标准模型（SM）相同的水平上对最小超对称标准模型（MSSM）进行辐射修正，已被开发并用于对LEP、SLC和Tevatron的所有弱电数据以及CLEO的辐射b->sgamma衰变进行全局拟合。 在SM和MSSM中，得到了在$M_Z$尺度和$\sin^2\theta_{\overline{MS}}$处的强耦合常数值。 最近在1996年夏季华沙会议上提出的弱电数据更新，将R_b异常从3.2 sigma降低到1.8 sigma。 此外，$b \to s\gamma$衰变比SM预测低30%。 在MSSM中，轻的停止子和轻的带电粒子会增加$R_b$并减少$b \to s\gamma$的速率，因此这两种观察结果可以在参数空间的同一区域内与MSSM相一致。 然而，MSSM拟合得到的$\chi^2$值仅略有降低，并且此外，停止子区的分裂必须异常高。 显示英文摘要

摘要： A program including all radiative corrections to the MSSM at the same level as the radiative corrections to the SM has been developed and used to perform global fits to all electroweak data from LEP, SLC and the Tevatron and the radiative b->sgamma decay from CLEO. Values of the strong coupling constant at the $M_Z$ scale and $\sin^2\theta_{\overline{MS}}$ are derived, both in the SM and MSSM. Recent updates on electroweak data, which have been presented at the Warsaw Conference in summer 1996, reduce the R_b anomaly from a 3.2 sigma to a 1.8 sigma effect. In addition, the $b \to s\gamma$ decay is 30% below the SM prediction. In the MSSM light stops and light charginos increase $R_b$ and decrease the $b \to s\gamma$ rate, so both observations can be brought into agreement with the MSSM for the same region of parameter space. However, the resulting $\chi^2$ value for the MSSM fits is only marginally lower and in addition, the splitting in the stop sector has to be unnaturally high.