Experimental verification of Coulomb de-excitation in pionic hydrogen A. Badertscher, M. Daum, P. F. A. Goudsmit, M. Janousch, P.-R. Kettle, J. Koglin, V. E. Markushin, J. Schottmüller and Z. G. Zhao Europhys. Lett., 54 3 (2001) 313-319 Published online: 01 December 2003 DOI: 10.1209/epl/i2001-00243-1