Scalar resonances: scattering and production amplitudes
Abstract
Description
Scattering and production amplitudes involving scalar resonances are known, according to Watson's theorem, to share the same phase $δ(s)$. We show that, at low energies, the production amplitude is fully determined by the combination of $δ(s)$ with another phase $ω(s)$, which describes intermediate two-meson propagation and is theoretically unambiguous. Our main result is a simple and almost model independent expression, which generalizes the usual $K$-matrix unitarization procedure and is suited to be used in analyses of production data involving scalar resonances.
10 pages, 4 figures. Minor changes, references added, version to appear in Phys. Rev. D
10 pages, 4 figures. Minor changes, references added, version to appear in Phys. Rev. D