Hadronic shift in pionic hydrogen
Résumé
The hadronic shift in pionic hydrogen has been redetermined to be epsilon(1s) = 7.086 +/- 0.007(stat) +/- 0.006(sys) eV by X-ray spectroscopy of ground-state transitions applying various energy calibration schemes. The experiment was performed at the high-intensity low-energy pion beam of the Paul Scherrer Institut by using the cyclotron trap and an ultimate-resolution Bragg spectrometer with bent crystals.