Development of cluster finding logic for the K_L→π^0υυ^^- experiment

Research Project

Project/Area Number	11640285
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	素粒子・核・宇宙線
Research Institution	Saga University
Principal Investigator	TSUKAMOTO Toshio Saga Univ., Faculty of Sci.and Engn., Assoc.Prof., 理工学部, 助教授 (40217287)
Project Period (FY)	1999 – 2000
Project Status	Completed (Fiscal Year 2000)
Budget Amount *help	¥3,500,000 (Direct Cost: ¥3,500,000) Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000) Fiscal Year 1999: ¥2,400,000 (Direct Cost: ¥2,400,000)
Keywords	Neutral Kaon / Experimental Elemental Particle Physics / Rare Decay Process / Direct CP Violation / 中性K中間子稀崩壊 / カロリメタートリガー / クラスター認識
Research Abstract	The detection of the process K_L→π^0υυ^^- is one of the the ways to establish a direct CP violation. In the first year, we have examined the scheme for the trigger and found that sufficient efficiencies to K_L→π^0υυ^^- as well as K_L→2γ, K_L→2π^0 and K_L→3π^0. In the second year, we actually constructed the neutral beam line at KEK and examine the profiles of it. The neutral beam line is hard to control the background which is, however, crucial for the experiment. We have found that the flux of the thermal neutrons in the halo of the beam agrees well with the expectation of the Monte Carlo simulation. The other sources of the background is in general are well described by the Monte Carlo except for the charged particles in the halo. We are trying to measure the flux of Kaon itself. In parallel, we have performed the test beam experiment for the CsI calorimeters which are the main part of the actual experiment. We have found that the energy resolution of about 2% at 1 GeV. In the actual experiment, CsI will be used in the vacuum. We have examined the behavior of the photo multipliers in the vacuum.