Studies of charm production and a search for exotic states at the CERN-SPS hyperon beam

We report results from the hyperon beam experiment WA89 at the CERN-SPS for which particle identification provided by the Omega-RICH was essential. One item is the measurement of inclusive production cross-sections of charmed hadrons, where K− identification greatly enhanced the purity of the observed samples. These measurements further confirmed the existence of the leading particle effect also in charm production. A second item is the search for the exotic state U(3100) decaying to Λ, p̄ and pions. No signal was found.