Antiproton-hydrogen annihilation at subkelvin temperatures
Résumé
The main properties of the interaction of ultralow-energy antiprotons (E<~10-6 a.u.) with atomic hydrogen are established. They include the elastic and inelastic cross sections and protonium (Pn) formation spectrum. The inverse Auger process (Pn+e→H+p̅) is taken into account in the framework of a unitary coupled-channel model. The annihilation cross section is found to be several times smaller than the predictions made by the black sphere absorption models. A family of p̅H near-threshold metastable states is predicted. The dependence of protonium formation probability on the position of such near-threshold S-matrix singularities is analyzed. An estimation for the HH¯ annihilation cross section is obtained.
