Isospin mixing effects in low-energy $\bar{K}N-\pi \Sigma$ interaction

Abstract

New strong coupled-channel $\bar{K}N-\pi \Sigma$ potential, reproducing all existing experimental data and suitable for using in an accurate few-body calculations, is constructed. Isospin breaking effects of direct inclusion of the Coulomb interaction and using of physical masses in calculations are investigated. The $1s$ level shift and width of kaonic hydrogen, consistent with the scattering data, was obtained and the corresponding exact strong $K^{-}p$ scattering length was calculated. One- and two-pole form of $\Lambda (1405)$ resonance was considered.

Comments: 24 pages, 5 tables, 4 figures; one sentence was changed and one reference added