Search forΣ−Hyperfragments

A systematic search has been undertaken for possible ${\Sigma }^{-}$ compounds produced by $K^{-}$ captures in nuclear emulsion. Mass determinations were performed on (a) 15 decays in flight into a charged pion and (b) 84 events resulting in capture configurations; the number of these events produced in single-nucleon $K^{-}$ captures is estimated to be >32 but ${\Sigma }^{-}$. The 4 events are discussed in detail and it is concluded that, although the (${\Sigma }^{-}n$) interpretation cannot be ruled out for 3 of them, in no case is the identification unequivocal.