Hyperon production in $Lambda_c^+to K^-ppi^+$ and $Lambda_c^+to K^0_Sppi^0 $

We investigate $S=-1$ hyperon production from the $Lambda_c^+to K^-ppi^+$ and $Lambda_c^+to K^0_Sppi^0$ decays within the effective Lagrangian approach. We consider the $Sigma/Lambda$ ground states, $Lambda(1520)$, $Lambda(1670)(J^p=1/2^-)$, $Lambda(1890)(J^p=3/2^+)$; $Lambda/Sigma$-pole contributions from the combined resonances between 1800 MeV and 2100 MeV; and $N/Delta$-pole and $K^ast$-pole contributions, which include the proton, $Delta(1232)$, and $K(892)$. We calculate the Dalitz plot density $(d^2Gamma/dM_{K^-p}dM_{K^-pi^+}$) for the $Lambda_c^+to K^-ppi^+$ decay. The calculated result is in good agreement with experimental data from the Belle Collaboration. Using the parameters from the fit, we present the Dalitz plot density for the $Lambda_c^+to K^0_Sppi^0$ decay. In our calculation, a sharp peak-like structure near 1665 MeV is predicted in the $Lambda_c^+to K^-ppi^+$ decay because of the interference effects between the $Lambda(1670)$ resonance and $eta$-$Lambda$ loop channels. We also demonstrate that we can access direct information regarding the weak couplings of $Lambda(1670)$ and $Sigma(1670)$ from the $Lambda_c^+to K^0_Sppi^0$ decay. Finally, a possible interpretation for the 1665 MeV structure beyond our prediction is briefly discussed.