2,550 research outputs found
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
Sigma, Kappa and fo(980) in E791 and BES II data
Both sigma and kappa are well established from E791 data on D->3pi and
D->K-pi-pi$ and BES II data on J/Psi->omega-pi-pi and KKpipi. Fits to these
data are accurately consistent with pi-pi and Kpi elastic scattering when one
allows for the Adler zero which arises from Chiral Symmetry Breaking. The phase
variation with mass is also consistent between elastic scattering and
production data.Comment: 15 pages, 8 figures. A shortened version of hep-ex.0510014,
conforming to page restrictions for Hadron05 Proceeding
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