Search for narrow states in antineutron-proton total and annihilation cross-sections near N-barN threshold

The n-barp total and annihilation cross sections have been measured from near N-barN threshold (1880 MeV) to 1940 MeV with RMS resolution ranging from 0.08 MeV (1880 MeV) to 6.7 MeV (1940 MeV). No significant narrow meson structures were seen, with 90% C.L. upper limits of 40--180 mb-MeV on σ/sub T/ for states with width less than our resolution. Combined with increasing unitarity bounds on σ as one approaches threshold, these limits confine widths of possible predicted states below 1900 MeV to less than ∼1 MeV