Precision measurement of the 3d→2p x-ray energy in kaonic 4He

• DOI: 10.1016/j.physletb.2007.08.032
• Publication Date: 2007-08-18T11:16:50Z
• Authors: S. Okada; G. Beer; H. Bhang; M. Cargnelli; J. Chiba; Seonho Choi; C. Curceanu; Y. Fukuda; T. Hanaki; R.S. Hayano; M. Iio; T. Ishikawa; S. Ishimoto; T. Ishiwatari; K. Itahashi; M. Iwai; M. Iwasaki; B. Juhász; P. Kienle; J. Marton; Y. Matsuda; H. Ohnishi; H. Outa; M. Sato; P. Schmid; S. Suzuki; T. Suzuki; H. Tatsuno; D. Tomono; E. Widmann; T. Yamazaki; H. Yim; J. Zmeskal
• Keywords: Balmer series

We have measured the Balmer-series x-rays of kaonic $^4$He atoms using novel large-area silicon drift x-ray detectors in order to study low-energy $\bar{K}$-nucleus strong interaction. The energy $3d \to 2p$ transition was determined be 6467 $\pm$ 3 (stat) 2 (syst) eV. resulting strong-interaction energy-level shift is agreement with theoretical calculations, thus eliminating a long-standing discrepancy between theory and experiment.