FORMATION OF ANTIHYDROGEN IN THE GROUND-STATE ANTI N=2 LEVEL

The cross sections of antihydrogen formation in the ground state and n=2 level by the impact of antiprotons on the ground state of positronium have been calculated under the framework of the eikonal approximation for incident energy of 30-1000 keV. The excited-state capture cross sections are quite appreciable and are even larger than the ground-state cross sections for impact energies ≤75 keV. The total eikonal cross sections (σ= σ1s+σ2s+σ2p) are always higher than the corresponding first-order Born approximation cross section throughout the present energy span. © 1995 The American Physical Society.