标题： SLC处弱电参数的测定 显示英文标题

标题： Determination of Electroweak Parameters at the SLC

摘要： 我们给出了Z玻色子产生于正负电子对撞的左-右横截面不对称度Alr的一个改进测量。 该测量是在91.28 GeV的质心能量下，在1994-95运行期间使用SLAC直线对撞机（SLC）上的SLD探测器进行的。 在此运行期间，SLC电子束的亮度加权平均极化被测量为(77.23 ± 0.52)%。 利用一个包含93,644个强子Z衰变样本，我们测量了极点不对称度Alr0为0.1512 ± 0.0042(统计) ± 0.0011(系统)，这相当于一个有效的弱混合角为0.23100 ± 0.00054(统计) ± 0.00014(系统)。 我们还给出了从轻子Z衰变观测到的微分横截面得出的Z轻子耦合不对称度A_e、A_μ和A_τ的一个初步直接测量结果。 我们将这些结果与我们之前的Alr测量结果结合起来，得到了弱混合角的联合确定值为0.23061 ± 0.00047。 显示英文摘要

摘要： We present an improved measurement of the left-right cross section asymmetry Alr for Z boson production by e+e- collisions. The measurement was performed at a center-of-mass energy of 91.28 GeV with the SLD detector at the SLAC Linear Collider (SLC) during the 1994-95 running period. The luminosity-weighted average polarization of the SLC electron beam during this run was measured to be (77.23 +/- 0.52)%. Using a sample of 93,644 hadronic Z decays, we measure the pole asymmetry Alr0 to be 0.1512 +/- 0.0042(stat.) +/- 0.0011(syst.) which is equivalent to an effective weak mixing angle of 0.23100 +/- 0.00054(stat.) +/- 0.00014(syst.). We also present a preliminary direct measurement of the Z-lepton coupling asymmetries A_e,A_mu, and A_tau extracted from the differential cross section observed in leptonic Z decays. We combine these results with our previous Alr measurement to obtain a combined determination of the weak mixing angle of 0.23061 +/- 0.00047.