Acceleration of pπ-atoms in a Coulomb de-excitation cascade

Abstract
An improved adiabatic approach (IAA) previously proposed in atomic physics is extended to the case of collisions of mesic atoms in excited states n⩾2. The computed rates λnnC(E) of the Coulomb de-excitation processes ()n+p→()n+p are substantially different from the IAA results. It is shown that the Coulomb de-excitation rates λnnC are high enough to explain the appearance of mesic atoms with kinetic energy ∼70 eV, which were observed in [J. E. Crawford, M. Daum, R. Frosch, et al., Phys. Lett. B 213, 391 (1988) and Phys. Rev. D 43, 46 (1991)].