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تسجيل مستخدم جديدPrecision measurement of the $3d to 2p$ x-ray energy in kaonic $^4$He
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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 the low-energy $bar{K}$-nucleus strong interaction. The energy of the $3d to 2p$ transition was determined to be 6467 $pm$ 3 (stat) $pm$ 2 (syst) eV. The resulting strong-interaction energy-level shift is in agreement with theoretical calculations, thus eliminating a long-standing discrepancy between theory and experiment.
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Kaonic hydrogen atoms provide a unique laboratory to probe the kaon-nucleon strong interaction at the energy threshold, allowing an investigation of the interplay between spontaneous and explicit chiral symmetry breaking in low-energy QCD. The SIDDHA
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We report a 0.08 % measurement of the bound neutron scattering length of $^4$He using neutron interferometry. The result is $b = (3.0982 pm 0.0021 mbox{ [stat]} pm 0.0014 mbox{ [sys]}) mbox{ fm}$. The corresponding free atomic scattering length is $a
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Very recently, we have performed a couple of experiments, {it{KEK PS-E549/E570}}, for the detailed study of the strange tribaryon $S^0(3115)$ obtained in {it{KEK PS-E471}}. These experiments were performed to accumulate much higher statistics with im
proved experimental apparatusespecially for the better proton spectroscopy of the $^4$He({it{stopped K}}$^-$, {it{N}}) reaction. In contrast to the previous proton spectrum, no narrow ($sim$ 20 MeV) peak structure was found either in the inclusive $^4$He({it{stopped K}}$^-$, {it{p}}) or in the semi-inclusive $^4$He({it{stopped K}}$^-$, {it{p}}$X^pm$) reaction channel, which is equivalent to the previous $E471$ event trigger condition. Detailed analysis of the present data and simulation shows that the peak, corresponding to $S^0(3115)$, has been an experimental artifact. Present analysis does not exclude the possible existence of a much wider structure. To be sensitive to such structure and for better understanding of the non-mesonic $K^-$ absorption reaction channel, detailed analysis of the data is in progress.
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