Analysis of the Λp enhancement at 2.129 GeV in the reaction K−d→π−Λp

Analyzing the cross section of the reaction ${K}^{\ensuremath{-}}d\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\Lambda}p$ in the region of the invariant $\ensuremath{\Lambda}p$ mass of 2.129 GeV we show that this enhancement is the combined effect of a cusp due to the deuteron and a sharp maximum in the scattering matrix element for the reaction $\ensuremath{\Sigma}N\ensuremath{\rightarrow}\ensuremath{\Lambda}N$ at ${m}_{\ensuremath{\Lambda}p}\ensuremath{\approx}2.125\ensuremath{-}2.127$ GeV.