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The kappa in E791 data for D->K-pi-pi
A combined fit is made to E791 data on D->K-pi-pi, LASS data on K-pi elastic
scattering, and BES II data on J/Psi->K*(890)-K-pi.In all cases, the K-pi
S-wave is fitted well with a kappa resonance and Ko(1430); the kappa requires
an s-dependent width with an Adler zero near threshold. The pole position of
the kappa is at M - iGamma/2 = (750 +30 -55) - i(342 +- 60) MeV. The E791
collaboration fitted their data using a form factor for the production process
D->kappa-pi. It is shown that this form factor is not needed. The data require
point-like production with an RMS radius <0.38 fm with 95 percent confidence.Comment: 11 pages, 4 figures. Typos corrected. Material added to explain how a
pole is possible without the phase shift on the real s-axis going through 90
degree
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