Precision spectroscopy of kaonic helium-3 and helium-4 3d→ 2p X-rays

T. Ishiwatari, M. Bazzi, H. Bhang, G. Beer, L. Bombelli, A. M. Bragadireanu, M. Cargnelli, S. Choi, G. Corradi, C. Curceanu, A. D. Uffizi, S. Enomoto, C. Fiorini, T. Frizzi, H. Fujioka, Y. Fujiwara, F. Ghio, B. Girolami, C. Guaraldo, T. HashimotoR. S. Hayano, T. Hiraiwa, M. Iio, M. Iliescu, S. Ishimoto, K. Itahashi, M. Iwasaki, P. Kienle, H. Kou, P. L. Levi Sandri, A. Longoni, V. Lucherini, J. Marton, Y. Matsuda, H. Noumi, H. Ohnishi, S. Okada, H. Outa, D. Pietreanu, T. Ponta, A. Rizzo, A. R. Romero Vidal, F. Sakuma, M. Sato, A. Scordo, M. Sekimoto, H. Shi, D. L. Sirghi, F. Sirghi, T. Suzuki, K. Tanida, H. Tatsuno, M. Tokuda, D. Tomono, A. Toyoda, K. Tsukada, A. Tudorache, V. Tudorache, O. Vazquez Doce, E. Widmann, B. Wünschek, T. Yamazaki, J. Zmeskal

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Recently, the shift of the kaonic helium-4 2p state was precisely determined by the E570 and SIDDHARTA experiments. Prior to the experiment by E570, the average of three earlier experimental results showed - 43±8 eV, while most of the theoretical calculations give ∼ 0 eV. This five-sigma discrepancy between theory and experiment was known as the "kaonic helium puzzle". A recent theoretical model showed a possible resonance-like shift of maximum 10 eV for a certain value of a deep antikaon-nucleon interaction potential, which is different in helium 3 and helium 4. The E570 experiment determined the shift of the kaonic helium-4 2p state as +2±2 (stat)±2 (sys) eV in 2007. The SIDDHARTA experiment determined the shift as 0±6 (stat)±2 (sys) eV in 2009. The results of these experiments resolved the long-standing puzzle. A new experiment of the kaonic helium-3 X-ray measurement is being prepared by the J-PARC E17 collaborators, and the kaonic helium-3 X-ray data taken very recently by the SIDDHARTA experiment are on the way to be analyzed. The results of the E570, E17 and SIDDHARTA experiments examine the strong interaction for light nuclei with different isospin, and test furthermore recent theoretical predictions.

Original languageEnglish
Title of host publicationHadron 2009 - Proceedings of the XIII International Conference on Hadron Spectroscopy
Number of pages5
Publication statusPublished - 2010
Event13th International Conference on Hadron Spectroscopy, Hadron 2009 - Tallahassee, FL, United States
Duration: 2009 Nov 292009 Dec 4

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Other13th International Conference on Hadron Spectroscopy, Hadron 2009
Country/TerritoryUnited States
CityTallahassee, FL


  • Exotic atoms
  • Kaonic helium
  • Silicon drift detector

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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