@article{026ba2b5e1444cfda04388e52aa61eb6,
title = "Spectroscopy of Pionic Atoms in Sn 122 (d, He 3) Reaction and Angular Dependence of the Formation Cross Sections",
abstract = "We observed the atomic 1s and 2p states of π- bound to Sn121 nuclei as distinct peak structures in the missing mass spectra of the Sn122(d,He3) nuclear reaction. A very intense deuteron beam and a spectrometer with a large angular acceptance let us achieve a potential of discovery, which includes the capability of determining the angle-dependent cross sections with high statistics. The 2p state in a Sn nucleus was observed for the first time. The binding energies and widths of the pionic states are determined and found to be consistent with previous experimental results of other Sn isotopes. The spectrum is measured at finite reaction angles for the first time. The formation cross sections at the reaction angles between 0° and 2° are determined. The observed reaction-angle dependence of each state is reproduced by theoretical calculations. However, the quantitative comparison with our high-precision data reveals a significant discrepancy between the measured and calculated formation cross sections of the pionic 1s state.",
author = "{piAF Collaboration} and T. Nishi and K. Itahashi and Berg, {G. P.A.} and H. Fujioka and N. Fukuda and N. Fukunishi and H. Geissel and Hayano, {R. S.} and S. Hirenzaki and K. Ichikawa and N. Ikeno and N. Inabe and S. Itoh and M. Iwasaki and D. Kameda and S. Kawase and T. Kubo and K. Kusaka and H. Matsubara and S. Michimasa and K. Miki and G. Mishima and H. Miya and H. Nagahiro and M. Nakamura and S. Noji and K. Okochi and S. Ota and N. Sakamoto and K. Suzuki and H. Takeda and Tanaka, {Y. K.} and K. Todoroki and K. Tsukada and T. Uesaka and Watanabe, {Y. N.} and H. Weick and H. Yamakami and K. Yoshida",
note = "Funding Information: The authors thank Professor Emeritus Dr. Toshimitsu Yamazaki for fruitful discussions and late Professor Emeritus Dr. Paul Kienle for his guidance in this study. The authors are grateful to the staffs of GSI for providing target materials and staffs of RIBF for stable operation of the facility. This experiment was performed at RI Beam Factory operated by RIKEN Nishina Center and CNS, University of Tokyo. This work is partly supported by MEXT Grants-in-Aid for Scientific Research on Innovative Areas (Grants No. JP22105517, No. JP24105712, and No. JP15H00844), JSPS Grants-in-Aid for Scientific Research (B) (Grant No. JP16340083), (A) (Grant No. JP16H02197), and (C) (Grants No. JP20540273 and No. JP24540274), Grant-in-Aid for JSPS Research Fellow (Grant No. 12J08538), the Bundesministerium f{\"u}r Bildung und Forschung, and the National Science Foundation through Grant No. Phys-0758100, and the Joint Institute for Nuclear Astrophysics through Grants No. Phys-0822648 and No. PHY-1430152 (JINA Center for the Evolution of the Elements). Publisher Copyright: {\textcopyright} 2018 American Physical Society.",
year = "2018",
month = apr,
day = "13",
doi = "10.1103/PhysRevLett.120.152505",
language = "English",
volume = "120",
journal = "Physical review letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "15",
}