Search for Charmed Hadrons Using a Direct-Muon Trigger

We present cross-section upper limits for the production of narrow states produced in 15.5-GeV ${\pi }^{+}N$ collisions, in coincidence with single muons. These limits are derived from an invariant-mass search involving all charged-hadron tracks in the final state, as observed in a large streamer chamber. We also give upper limits for the production of muon-associated ${\Lambda }^0$ and $K^0$ particles.