57 research outputs found

    First measurement of kaonic helium-3 X-rays

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    The first observation of the kaonic 3He 3d - 2p transition was made using slow K- mesons stopped in a gaseous 3He target. The kaonic atom X-rays were detected with large-area silicon drift detectors using the timing information of the K+K- pairs of phi-meson decays produced by the DAFNE e+e- collider. The strong interaction shift of the kaonic 3He 2p state was determined to be -2+-2 (stat)+-4 (syst) eV.Comment: Accepted for publication in Phys. Lett.

    A New Measurement of Kaonic Hydrogen X rays

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    The KˉN\bar{K}N system at threshold is a sensitive testing ground for low energy QCD, especially for the explicit chiral symmetry breaking. Therefore, we have measured the KK-series x rays of kaonic hydrogen atoms at the DAΦ\PhiNE electron-positron collider of Laboratori Nazionali di Frascati, and have determined the most precise values of the strong-interaction energy-level shift and width of the 1s1s atomic state. As x-ray detectors, we used large-area silicon drift detectors having excellent energy and timing resolution, which were developed especially for the SIDDHARTA experiment. The shift and width were determined to be ϵ1s=283±36±6(syst)\epsilon_{1s} = -283 \pm 36 \pm 6 {(syst)} eV and Γ1s=541±89(stat)±22(syst)\Gamma_{1s} = 541 \pm 89 {(stat)} \pm 22 {(syst)} eV, respectively. The new values will provide vital constraints on the theoretical description of the low-energy KˉN\bar{K}N interaction.Comment: 5 figures, submitted to Physics Letters

    Measurements of the strong-interaction widths of the kaonic 3He and 4He 2p levels

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    The kaonic 3He and 4He X-rays emitted in the 3d-2p transitions were measured in the SIDDHARTA experiment. The widths of the kaonic 3He and 4He 2p states were determined to be Gamma_2p(3He) = 6 \pm 6 (stat.) \pm 7 (syst.) eV, and Gamma_2p(4He) = 14 \pm 8 (stat.) \pm 5 (syst.) eV, respectively. Both results are consistent with the theoretical predictions. The width of kaonic 4He is much smaller than the value of 55 \pm 34 eV determined by the experiments performed in the 70's and 80's, while the width of kaonic 3He was determined for the first time.Comment: Accepted in Phys. Lett.

    Kaonic3He and4He measurements in the SIDDHARTA experiment at the DAΦNE collider

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    The SIDDHARTA collaboration measured kaonic 3 He and 4 He 3d → 2p X-rays with gaseous targets at the DAΦNE e + e − collider. The 2p -state strong-interaction shifts and widths were precisely determined by using 144 high-resolution silicon drift detectors. The shift of K −4 He is in good agreement with theoretical calculations and consistent with the recent experimental result of KEK-PS E570. The shift of K −3 He is also determined for the first time. The newly determined widths are in agreement with optical model calculations
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