Dr Shinji Okada (LNF-INFN)
The SIDDHARTA collaboration have measured the K-series x-rays of kaonic hydrogen atoms with significant improvements over the previous experiments, and precisely determined the strong-interaction energy-level shift and width of the 1s atomic state. The measurement offers a unique possibility to determine the KN s-wave scattering lengths, which is one of the most important observable to investigate chiral SU(3) dynamics in low-energy QCD and the role of explicit chiral symmetry-breaking due to the relatively large strange quark mass. It is also strongly related to recent hot topics of the structure of the Lambda(1405) resonace and possible deeply bound kaonic systems. The result will set tight constraints on those theories. The experiment has been performed at the DAFNE e+e- collider which produces the phi-resonance that decays into K+K-. The resulting low energy K-'s with small energy spread are well suited to be stopped in a gas target efficiently for producing these atoms. As x-ray detectors, we employed novel large-area silicon drift detectors having higher energy and timing resolution than in previous experiments, which were developed especially for this experiment. In this talk, our final results on kaonic hydrogen will be presented, and future plans will be as well discussed.
Dr Shinji Okada (LNF-INFN)
Dr Alberto CLOZZA (LNF-INFN) Dr Alessandro D'UFFIZI (LNF-INFN) Mr Alessandro RIZZO (LNF-INFN) Dr Alessandro SCORDO (LNF-INFN) Ms Alexandra TUDORACHE (IFIN-HH) Prof. Antonio LONGONI (Politecnico di Milano) Dr Antonio ROMERO VIDAL (LNF-INFN) Dr Bruno GIROLAMI (INFN Sez. di Roma I and Inst. Superiore di Sanita) Dr Carlo FIORINI (Politecnico di Milano) Prof. Carlo GUARALDO (LNF-INFN) Ms Carolina BERUCCI (LNF-INFN) Dr Catalina CURCEANU (LNF-INFN) Ms Diana SIRGHI (LNF-INFN, IFIN-HH) Mr Dorel PIETREANU (LNF-INFN) Prof. Eberhard WIDMANN (Stefan Meyer Institut) Mr Florin SIRGHI (LNF-INFN, IFIN-HH) Dr Francesco GHIO (INFN Sez. di Roma I and Inst. Superiore di Sanita) Prof. George BEER (Univ. of Victoria) Mr Giovanni CORRADI (LNF-INFN) Mr Hexi SHI (Univ. of Tokyo) Dr Hideyuki TATSUNO (Univ. of Tokyo) Prof. Johann MARTON (Stefan Meyer Institut) Dr Johann ZMESKAL (Stefan Meyer Institut) Mr Kristian PISCICCHIA (LNF-INFN) Dr Luca BOMBELLI (Politecnico di Milano) Dr Marco POLI LENER (LNF-INFN) Dr Mario BRAGADIREANU (IFIN-HH) Prof. Masahiko IWASAKI (RIKEN, Tokyo Institute of Technology) Mr Massimiliano BAZZI (LNF-INFN) Dr Michael CARGNELLI (Stefan Meyer Institut) Dr Mihai ILIESCU (LNF-INFN, IFIN-HH) Dr Oton VAZQUEZ DOCE (LNF-INFN) Dr Paolo LEVI SANDRI (LNF-INFN) Prof. Paul KIENLE (Stefan Meyer Institut, Tech. Univ. Munchen) Prof. Ryugo HAYANO (Univ. of Tokyo) Dr Titus PONTA (IFIN-HH) Dr Tommaso FRIZZI (Politecnico di Milano) Dr Tomoichi ISHIWATARI (Stefan Meyer Institut) Ms Valentina TUDORACHE (IFIN-HH) Prof. Vincenzo LUCHERINI (LNF-INFN)