A new measurement of kaonic hydrogen X-rays

作者：Bazzi M; Beer G; Bombelli L; Bragadireanu A M; Cargnelli M^*; Corradi G; Curceanu C; d'Uffizi A; Fiorini C; Frizzi T; Ghio F; Girolami B; Guaraldo C; Hayano R S; Iliescu M; Ishiwatari T; Iwasaki M; Kienle P; Sandri P Levi; Longoni A; Lucherini V; Marton J; Okada S; Pietreanu D; Ponta T; Rizzo A; Vidal A Romero; Scordo A; Shi H; Sirghi D L; Sirghi F; Tatsuno H; Tudorache A; Tudorache V; Doce O Vazquez; Widmann E

来源：Physics Letters B, 2011, 704(3): 113-117.

DOI：10.1016/j.physletb.2011.09.011

• Kaonic atoms
• Low-energy QCD
• Antikaon-nucleon physics
• X-ray detection

The (K) over barN system at threshold is a sensitive testing ground for low energy QCD, especially for the explicit chiral symmetry breaking. Therefore, we have measured the K-series X-rays of kaonic hydrogen atoms at the DA Phi NE 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 Is 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 epsilon(1s) = -283 +/- 36(stat) +/- 6(syst) eV and Gamma(1s) = 541 +/- 89(stat) +/- 22(syst) eV, respectively. The new values will provide vital constraints on the theoretical description of the low-energy (K) over barN interaction.

• 出版日期2011-10-13