Electron-Positron Collision Experiment with SLAC・SLD Detector

为了对粒子物理学中的“标准模型”进行详细的研究，我们在SLAC直线对撞机（SLC）的e^+e^-碰撞点上建造了SLAC大型探测器（SLD）。实验的目标是积累10^4到10^5个Z^0事件，其中“极化电子束”和“正电子束”在92 GeV左右碰撞。1989年至1991年，日本组与SLAC A组和B组合作，参与了中心漂移室（CDC）和克伦科夫环成像探测器（CRID）的建造和运行。这次实验的特点是首次使用了“极化电子束”，对sin ^2 rheta_W的灵敏度提高了100倍以上（rheta_<W '> Weinberg角），电弱理论的关键参数，通过总截面的前后不对称性。SLD/SLC实验相对于现有探测器的优点是：碰撞点处光束尺寸小，顶点确定精确 ...更多信息 用顶点探测器（VTX）、中心漂移室（CDC）、切伦科夫环成像探测器（CRID）和液氩电磁（LAC）及气体取样强子量热计（WIC）进行了良好的粒子鉴别和量热测量。并于1991年2月被移到凿好的位置。1991年4月至7月进行了第一次梁试运行。在该运行中，加速器被调谐以提供更高的强度而没有偏振束。在这些测试运行之后，探测器的一些剩余部件已在夏季关闭期间安装。从1991年10月中旬到年底，在60脉冲/秒的工作模式下，成功地进行了工程运行。我们总共获得了363个Z^0事件，净数据采集时间为103小时，其中总射束开启时间为170小时。实验结果表明，CDC跟踪系统的局部位置分辨率为97 mm，整体分辨率为123 mm。后者可以通过进一步的微型单元的位置校准调整到35 mm。CRID于1991年8月获得了第一张宇宙粒子通过的切伦科夫环图像，驯服气体完全成功地混合到复杂的气体循环系统中。我们希望在1992年3月至7月和1991年10月至12月以50Z^0秒/小时的速率（重复率为120 Hz）进行的高强度运行中，光束偏振度约为35%，能得到10^4 Z^0秒的校正。名古屋大学和东北大学已准备好计算机设置和数据分析准备。少

To proceed a detailed examination of "the standard model" in particle physics, the SLAC Large Detector (SLD) has been constructed and installed in the e^+e^- beam-collision point in the SLAC Linear Collider (SLC). The goal of experiment is to accumulate 10^4 to 10^5 Z^0 events with collision of "polarized electron beam" and "positron beam" at around 92 GeV. Japanese Group took parts in the construction and operation of Central Drift Chamber (CDC) and Crrenkov Ring Imaging Detector (CRID) from 1989 to 1991 under the cooperation with SLAC Group A and Group B.The unique feature of this experiment is that the first utilization of "Polarized electron beam" which provides more than 100 times sensitivity for sin^2rheta_W (rheta_<W'>Weinberg-angle), a key parameter of the electroweak theory, through the forward-backward asymmetry of total crosssections. The vantages of SLD/SLC experiment over other existing detectors are : a smaller beam size at collision point, a precise vertex determination … More by Vertex Detector (VTX), fme track determination by Central Drift Chamber (CDC), good particle identification with Cerenkov Ring Imaging Detector (CRID) and good calorimetry with liquid argon electromagnetic (LAC) and gas-sampling hadron calorimeters (WIC).The detector was completed in the Spring of 1990 and thoroughly tested with cosmic-rays from Summer to Fall in 1990, and was moved into the hewn position in February 1991. First test runs with beam was made from April to July 199 1. In this run, accelerator was tuned to provide higher intensities without polarized beam. After these test runs, some remaining parts of the detector had been installed in the period of Summer shutdown. The engineering runs were successfully done from the middle of October to the end of 1991 with beams of 60 pulses per second operation mode. We obtained total of 363 Z^0 events by net data acquisition time of 103hr., where the total beam on time was 170hr. and detector on time was 130hr.From these experiments, CDC tracking resolutions were turned out to be 97mm in local position resolution and 123mm in overall resolutions. The latter could be tuned up to 35mm by further position calibrations of mini-cells. CRID obtained first Cerenkov ring image for passage of cosmic particles in August 1991 and TAME gas mixing into the complex gas-circulating system was fully successful. We hope correction of 10^4 Z^0s from the high intensity runs at 50 Z^0 s/hour rate (repetition rate of 12OHz) scheduled from March to July 1992 and from October to December 199 1, with the beam polarization of about 35%. Computer setup and preparation for data analysis are ready in Nagoya and Tohoku Universities. Less