Study of CP Violation in the Neutral Kaon System

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The purpose of this project is to study the CP violation in the neutral kaon system from two fronts. One is to measure the double ratio of branching ratios of K_L, K_S*pi^0pi^0, and pi^+pi^- with a high precision (KTeV E832). The deviation of this ratio from unity is a proof of CP violation in the weak decay itself (direct CP violation). The other is to search for rare K_L decays where the effect of direct CP violation is dominant (KTeV E799).We have prepared the new experiments at Fermi National Accelerator Laboratory at U.S.A.. In particular, we were reponsible for the phototubes for the CsI electromagnetic calorimeter, fast data acquisition system, and a special photon veto counter.The experiment received the first neutral beam at the end of August 1995, and it was confirmed that the beam was clean as designed.We took data for E832 for 2 months in 1996, and started taking data for E799 from mid-January, 1997. With a couple of switchovers, we plan to take data till September, 1997. We expect to start having preliminary results sometime late 1997.We have also developed new silicon strip detectors for the B-factory experiment. After optimization with computer simulation, development of test system, and testing various prototypes, we have decided the final design. The mass production will start soon.