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

Experimental disagreements with Extended Unitarity

In production processes, e.g. J/Psi -> omega-pi-pi or pbar-p -> 3pi, the sigma and fo(980) overlap in the same partial wave. The conjecture of Extended Unitarity (EU) states that the pi-pi pair should have the same phase variation as pi-pi elastic scattering. This is an extension of Watson's theorem beyond its original derivation, which stated only that the s-dependence of a single resonance should be universal. The prediction of EU is that the deep dip observed in pi-pi elastic scattering close to 1 GeV should also appear in production data. Four sets of data disagree with this prediction. All require different relative magnitudes of sigma and fo(980). That being so, a fresh conjecture is to rewrite the 2-body unitarity relation for production in terms of observed magnitudes. This leads to a prediction different to EU. Central production data from the AFS experiment fit naturally to this hypothesis.Comment: 24 pages, 12 figures. To be published in Euro. Phys. J