Spectroscopy of Pionic Atoms in Sn 122 (d, He 3) Reaction and Angular Dependence of the Formation Cross Sections

piAF Collaboration

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


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.

Original languageEnglish
Article number152505
JournalPhysical Review Letters
Issue number15
Publication statusPublished - 13-04-2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


Dive into the research topics of 'Spectroscopy of Pionic Atoms in Sn 122 (d, He 3) Reaction and Angular Dependence of the Formation Cross Sections'. Together they form a unique fingerprint.

Cite this