We report high-precision calculations that correctly include the rearrangement channels by solving the modified Faddeev equations for energies between the $\mathrm{Ps}(n=2\mathrm{})$ and $\overline{\mathrm{H}}(n=3\mathrm{})$ thresholds, which involve six and eight open channels. We find that $99\%$ of the antihydrogen is formed in $\overline{\mathrm{H}}(n=2\mathrm{})$. Just above the $\mathrm{Ps}(n=2\mathrm{})$ threshold the $S$, $P$, and $D$ partial waves contribute nearly $1400\pi a_0^2$ near the maximum. We find evidence that the induced long-range dipole potential is responsible for such a large $\overline{\mathrm{H}}$ formation cross section. The possibility of utilizing this resonance to synthesize low-energy $\overline{\mathrm{H}}$ is discussed.

• Received 17 July 2001

DOI:https://doi.org/10.1103/PhysRevLett.88.063401