Hadronic shift in pionic hydrogen
  The hadronic shift in pionic hydrogen has been redetermined to be $\epsilon_{1s}=7.086\,\pm\,0.007(stat)\,\pm\,0.006(sys)$\,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. 
M. Hennebach, D. F. Anagnostopoulos, A. Dax, H. Fuhrmann, D. Gotta, A.   Gruber, A. Hirtl, P. Indelicato, Y.-W. Liu, B. Mani...
nucl-ex physics.atom-ph