Evidence of Ξ hypernuclear production in the 12C(K-, K+)Ξ12Be reaction -: art. no. 054603

The E885 Collaboration utilized the 1.8 GeV/cK(-) beam line at the Alternating Gradient Synchrotron (AGS) to accumulate greater than 10 times the world's existing data sample of (K-,Rf) events on carbon. A total of about 3x10(5) (K-,K+) events were collected and analyzed. drop hypernuclear states are expected to be produced through the reaction K- + C-12-->K+ + Be-12(drop). A signal could also result from direct production of (11)(Lambda)Bei+Lambda without a distinct drop intermediate state. The measured missing-mass spectrum indicates the existence of a signal below the threshold for free drop(-) production that cannot be explained by background or effects of limited resolution. Although the resolution was not sufficient to resolve discrete hypernuclear states, the excess of events in the region of missing mass, kinematically inaccessible in free drop(-) production, can be compared with theoretical predictions for Be-12(drop) production. Reasonable agreement between the data and theory is achieved by assuming a drop-nucleus potential well depth V-0 drop of about 14 MeV within the Woods-Saxon prescription.