Strong-Interaction Effects in Antiprotonic Atoms

We have measured the energies and widths of the x-ray lines from the $4f\to 3d$ transition in antiprotonic atoms of ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$. The results are discussed in terms of a phenomenological optical potential. We have also observed the x-ray line from the $3d\to 4p$ transition in the antiprotonic ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ atom.