Search for Narrowp¯pStates Produced by Meson Exchange

The results are reported of a search for narrow $\overline{p}p$ states in the mass range 1.9 to 2.5 ${\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c}}^2$ produced in the meson-exchange reaction ${\pi }^{+}p\to {\left(\overline{p}p\right)}_f{\Delta }^{++}$ at 9.8 GeV/c. This measurement is sensitive to production of the controversial $S\left(1935\right)\mathrm{}$ meson. It is also sensitive to multiquark exchange leading to the production of four-quark states. We find no evidence for narrow states at the ∼20-nb level.