T.Kobayashi1, O.Yamakawa1, K.Omata2, K.Sugimoto3, T.Shimoda3, N.Takahashi3, I.Tanihata4 High Energy Accelerator Res. Org. (KEK1 Institute for Nuclear Study, Univ. of Tokyo, Tanashi2 Osaka Univ., Osaka3 Inst.of Physical and Chemical Res. (RIKEN4
Physical Review Letters60(1988)2599