pi+pi- Atom in Chiral Theories
arXiv:hep-ph/9807474
Abstract
We review the existing theoretical approaches to the study of the observables of hadronic atoms. In the relativistic perturbative approach based on the Bethe-Salpeter equation and Chiral Perturbation Theory we derive the general expression for the pi+pi- atom lifetime. The lowest-order correction to the relativistic Deser-type formula for the atom width is predicted to be 6.1\pm 3.1 %.
7 pages, LaTeX-file (dubna98.sty) Talk given at the International Workshop "Hadronic Atoms and Posirtonium in the Standard Model", 26-31 May 1998, Dubna, Russia