SEARCH FOR STRANGE TRIBARYON STATES IN THE 4He(STOPPED K-, p) REACTION

We have measured a proton energy from the stopped K- reaction on 4He to search for strange tribaryon states at KEK 12 GeV PS. No statistically significant signal was observed in the missing mass spectrum obtained by the inclusive 4He(stopped K-, p) measurement. Upper limits of the formation branching ratio at the 95 % C.L. were derived for neutral tribaryon states with strangeness -1 to be (0.4 ~ 6) × 10-4, (0.2 ~ 6) × 10-3 and (0.06 ~ 5) × 10-2/(stopped K-) for assumed natural widths of 0, 20 and 40 MeV/c2, respectively.