The kappa in J/Ψ↦K+π
Queen Mary, University of London, E1 4NS, London, UK
* e-mail: D.Bugg@rl.ac.uk
Accepted: 16 April 2005
Published online: 24 May 2005
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 π -1 is close to the prediction 0.19±0.02 m π -1 of Chiral Perturbation Theory at O(p 4).
PACS: 13.25.Gv Decays of J/ψ, ϒ, and other quarkonia – / 14.40.Gx Mesons with S = C = B = 0, mass > 2.5 GeV (including quarkonia) –
© Società Italiana di Fisica and Springer-Verlag, 2005