Observation of Structure inp¯pandp¯dTotal Cross Sections below 1.1 GeV/c

Total cross sections of $\overline{p}p$ and $\overline{p}d$ have been measured between 360 and 1050 MeV/c, with high statistical precision. Structures are observed in both cross sections at about the same momenta. For $\overline{p}p$, the central mass is 1932±2 MeV/${\mathit{c}}^2$, and a fit to the data with a simple Breit-Wigner resonance plus background gives $\Gamma =9_{-3\mathrm{}}^{+4\mathrm{}}$ MeV/${\mathit{c}}^2$. The data suggest that the structures are in the isospin-1 state.