of Chiral Perturbation Theory
نویسنده
چکیده
BES II data for J/Ψ → K * (890)Kπ reveal a strong κ peak in the Kπ S-wave near threshold. Both magnitude and phase are determined in slices of Kπ mass by interferences with strong K 0 (1430), K 1 (1270) and K 1 (1400) signals. The phase variation with mass agrees within errors with LASS data for Kπ elastic scattering. A combined fit is presented to both BES and LASS data. The fit uses a Breit-Wigner amplitude with an s-dependent width containing an Adler zero. The κ pole is at (760±20(stat)±40(syst))−i(420± 45(stat)±60(syst)) MeV. The S-wave I = 0 scattering length a 0 = 0.23±0.04 m −1 π is close to the prediction 0.19 ± 0.02 m −1 π of Chiral Perturbation Theory at O(p 4).
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