| The E391a collaboration searched for rare kaon decays at the KEK 12 GeV proton synchrotron in Tsukuba, Japan. This thesis focuses on using a blind analysis to search for the rare decay K0L→p0p 0nn.&d1; In a blind analysis, the signal region is kept hidden while choosing event selection criteria. The background was estimated through the bifurcation method to be 0.26 +/- 0.18stat +/- 0.01 syst. The kaon flux is estimated to be (5.61 +/- 0.16 stat +/- 0.26syst) x 109. After opening the box, we observed zero event. Therefore, we set an upper limit of the branching ratio of the K0L→p0p 0nn&d1; decay at 1.1 x 10-6 at the 90% confidence level. |
