Affiliation: | (1) Research Development Corporation of Japan (JRDC), Sakigake kenkyu 21 PRESTO, c/o Muon Science Laboratory, The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351‐01, Japan;(2) Muon Science Laboratory, The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351‐01, Japan;(3) Meson Science Laboratory, Faculty of Science, The University of Tokyo, Hongo, Bunkyo‐ku, Tokyo 113, Japan |