S-wave resonance coupled-channel approach to the reactions ${\mathrm{\pi }}^{\mathrm{-}}$+p→η+n and ${\mathit{K}}^{\mathrm{-}}$+p→η+Λ, and a determination of the ηn and ηΛ scattering lengths

The total cross sections of the reactions ${\mathrm{\pi }}^{\mathrm{-}}$+p→η+n and ${\mathit{K}}^{\mathrm{-}}$+p→η+Λ near threshold have been calculated in an S-wave resonance coupled-channel approach. The ηN scattering length is [0.621±0.040+i(0.306±0.034)] fm and the ηΛ scattering length is [0.64±0.29+i(0.80±0.30)] fm. The large value of the ηΛ scattering length leads us to speculate on the possible existence of η-mesic hypernuclei. © 1996 The American Physical Society.