Electromagnetic corrections to $\ddot{I}{€}^{-}$p scattering length from pionic hydrogen

Abstract

We derive a closed, model space independent, expression for the electromagnetic correction factor $\hat{I}´$ to the scattering length $a$ extracted from a hydrogenic atom with an extended charge to order $\hat{I}{\pm }^2$ and $a^3$ in the limit of a short ranged hadronic interaction.

4 pages; PANIC02, XVIth Conference on Particles and Nuclei, Osaka, to appear in Nuclear Physics A