Groundstate Lamb-shift for hydrogen-like uranium measured at the ESR storage ring

The Lyman α transitions of hydrogen-like uranium associated with electron capture were measured in collisions of stored bare U92+ ions with gaseous targets at the storage ring ESR. By applying X-ray/particle coincidence techniques the groundstate transition energies in the rest frame could be determined with a precision of about 600 ppm. The experimental result is excellent agreement with the theoretical prediction for the groundstate Lamb-shift in hydrogen-like uranium and is already sensitive to the 2s Lamb-shift. (orig.)