Coulomb excitation and breakup of π⁺π^--atoms at high energies

We develop a semi-classical theory for the excitation and breakup of a π+π--atom moving at relativistic energies in the screened Coulomb field of a nucleus. Cross sections for various π+π--atomic transitions and target nuclei are evaluated analytically and numerically in first-order perturbation theory. Anticipating further refinement of our theory, special attention is devoted to identifying the various approximations and estimating their associated errors. © 1999 Elsevier Science B.V. All rights reserved.