Observation of a bound state in the C reaction at 1.8 GeV/

Nagae, Tomofumi*; Ekawa, Hiroyuki; Hasegawa, Shoichi   ; Hayakawa, Shuhei; Hosomi, Kenji  ; Ichikawa, Yudai   ; Imai, Kenichi; Kimbara, Shinji; Nanamura, Takuya*; Naruki, Megumi; Sako, Hiroyuki   ; Sato, Susumu  ; Tamura, Hirokazu*; Tanida, Kiyoshi   ; Yamamoto, Takeshi  ; 29 of others*

For the full understanding of baryon-baryon interactions in flavor , the interaction is the last missing piece of information. So far, we have revealed the interaction to be attractive ( MeV), and interaction to be repulsive in the medium to heavy mass-number region. The bonding energy is weakly attractive. While we have a few experimental observations suggesting the interaction would be attractive, there still exist large theoretical ambiguities weather it is attractive or not. Experimental determinations on the existence of bound states of hypernuclei by observing bound-state peaks are strongly awaited. In this report, a new preliminary result on the missing-mass spectrum of a C reaction, which strongly suggests the existence of -hypernuclear bound states, is presented.