Study of CP Violation in Weak Interaction

我们对费米实验室E731实验的数据进行了分析，并公布了CP破坏参数Re(epsilon‘/epsilon)的最终结果。我们还分析了费米实验室E799-I实验的数据，该实验的目的是寻找许多罕见的K_L衰变。我们在K_L*pi^0ee，K_L*pi^0mu，K_L*pi^0nunu，K_L*eee，K_L*eegamma，K_L*pi^0pi^0伽马，pi^0*ee和pi^0*mue上发表了新的结果。前三次衰变预计会有很大的直接CP破坏幅度。9.2.费米实验室KTeV实验的准备工作费米实验室KTeV实验将于1996年7月开始，将持续2年。实验将测量CP破坏参数Re(epsilon‘/epsilon)，精度提高6倍，达到1×10^~(-4)。它还将寻找灵敏度提高两个数量级的许多罕见的K_L衰变。我们对这项实验做出了以下贡献。*我们与加州大学洛杉矶分校和滨松光电子公司合作，为新的CSI量热计开发了一种新型的光电管。这种显像管的设计具有极佳的线性。我们建立了一个新的光电管测试系统，测量了2400个光电管的线性度和速率依赖关系，精度为0.2%。*我们已经与Fermilab合作开发了一种新的数据采集系统。该系统由大容量存储矩阵和高性能计算机组成。该系统可以读入和全面分析20 kHz的8kbyte事件，并将选定的事件写出磁带。*我们设计、测试并制作了专门的光子否决权计数器，放置在CSI量热计的束孔周围。*我们用蒙特卡罗模拟方法估计了各种罕见的K_L衰变的灵敏度和本底水平。我们还开发了衰变的分析代码。

We have analyzed the data from Fermilab E731 experiment, and published the final result on the CP violation parameter, Re (epsilon'/epsilon). We have also analyzed the data from Fermilab E799-I experiment, whose purpose was to search for many rare K_L decays. We have published new results on K_L*pi^0ee, K_L*pi^0mumu, K_L*pi^0nunu, K_L*eeee, K_L*eegammagamma, K_L*pi^0pi^0gamma, pi^0*ee, and pi^0*mue. The first three decays are expeted to have a large direct CP violation amplitude.9.2.Preparation of Fermilab KTeV experimentFermilab KTeV experiment will begin in July of 1996, and will run for 2 years. The experiment will measure the CP violation parameter Re (epsilon'/epsilon) with 6 times better accuracy, to 1x10^<-4>. It will also search for many rare K_L decays with a sensitively improved by two orders of magnitudes. We have made the following contributions to the experiment.*We have worked UCLA and Hamamatsu Photonics to develop a new type of phototubes for the new CsI calorimeter. The tube was designed to have an excellent linearity. We built a new phototube testing system, and measured the linearity and rate dependence of the 2400 tubes with <0.2% accuracy.*We have collaborated with Fermilab to develop a new data acquisition system. The system consists of a large memory matrix and high performance computers. This system can read in and fully analyze 8kbyte events coming at 20kHz, and write out selected events to tape.*We have designed, tested, and produced a specialized photon veto counter to be placed around the beam holes in the CsI calorimeter.*We have estimated the sensitivity and background levels for various rare K_L decays by using Monte Carlo simulation. We have also developped analysis codes for the decays.