Energy dependence of $K^-$-"$pp$" effective potential derived from coupled-channel Green's function

Abstract

We investigate the energy dependence of a single-channel effective potential between the $K^-$ and the "$pp$"-core nucleus, which can be obtained as an $K^-$-"$pp$" equivalent local potential from a coupled-channel model for $\bar{K}(NN)$-$\pi(\Sigma N)$ systems. It turns out that the imaginary part of the resultant potential near the $\pi \Sigma N$ decay threshold can well approximate the phase space suppression factor of $K^-pp \to \pi \Sigma N$ decay modes. The effects on the pole position of the $\pi(\Sigma N)$ state in the $\pi \Sigma N$ channel are also discussed.Comment: 4 pages, 2 figures, Proceedings of the International Conference on Exotic Atoms and Related Topics (EXA2011), September 5-9, 2011, Wien, Austria, to appear in Hyperfine Interaction