Discovery of the repulsive energy shift of the kaonic hydrogen 1s state

M. Iwasaki, K. Bartlett, G. A. Beer, D. R. Gill, R. S. Hayano, T. M. Ito, L. Lee, G. Mason, S. N. Nakamura, A. Olin, H. Outa, M. Salomon, R. Seki, T. Taniguchi, T. P. Terada, G. Trayling, Y. Yamashita, S. Yen

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


The aim in this manuscript is to clarify the progress in understanding the nature of the K̄N interaction at the lowest energy, given by the recent kaonic hydrogen X-ray experiment at KEK [1]. We have observed a clear spectrum showing the kaonic hydrogen Kα line, for the first time. The analysis gives the repulsive energy shift to be ΔE(1s) = -323 ± 63(statistical) ± 11 (systematic) eV and the energy width to be Γ(1s) = 407 ± 208 ± 100 eV. This result is consistent with analyses of the previous low-energy scattering data and resolves the long-standing kaonic hydrogen puzzle.

Original languageEnglish
Pages (from-to)501c-510c
JournalNuclear Physics A
Issue number1-2
Publication statusPublished - 1998 Aug 24
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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