The first precision measurement of deeply bound pionic states in 121Sn Takahiro Nishi, Georg P. A. Berg, Masanori Dozono, Hiroyuki Fujioka, Naoki Fukuda, Tatsuya Furuno, Hans Geissel, Ryugo S. Hayano, Naoto Inabe, Kenta Itahashi et al. (25 more) EPJ Web of Conferences, 66 (2014) 09014 Published online: 20 March 2014 DOI: 10.1051/epjconf/20146609014