Institution: | 1. Department of Physics , Ochanomizu University , Ohtsuka, Bunkyo-ku, Tokyo, 112, Japan;2. Institutefor Solid State Physics, The University of Tokyo , Roppongi, Minato-ku, Tokyo, 106, Japan;3. PF, National Laboratory for High Energy Physics , Oho, Tsukuba, Ibaraki, 305, Japan |