Extraction of ΛK−p and ΣK−p Coupling Constants from K±−p Forward Amplitudes

Abstract

The difficulty about the unphysical part of the cut of $K^{\pm }-p$ forward amplitudes is avoided by conformally mapping the unphysical and low-energy $K^{-}-p$ regions on the cut onto the boundary of an ellipse and the whole cut plane to the inside of the ellipse. A discrepancy function constructed on the physical region using experimental information on the $K^{\pm }-p$ forward amplitudes is stably extrapolated to estimate $\frac{({g_{\Lambda }}^2+0.8\mathrm{}{g_{\Sigma }}^2)}{4\pi }$ as ${14}_{-3\mathrm{}}^{+4\mathrm{}}$. The signs of the real part of $K^{-}-p$ forward amplitudes at high energies are found to be positive.