Hyperon production in Λc+ →k-pπ+ and Λc+ → KS0 pπ0

We investigate S=-1 hyperon production from the Λc+→K-pπ+ and Λc+→KS0pπ0 decays within the effective Lagrangian approach. We consider the ς/Λ ground states, Λ(1520), Λ(1670)(Jp=1/2-), Λ(1890)(Jp=3/2+); Λ/ς-pole contributions from the combined resonances between 1800 and 2100 MeV; and N/Δ-pole and K∗-pole contributions, which include the proton, Δ(1232), and K(892). We calculate the Dalitz plot density (d2Γ/dMK-pdMK-π+) for the Λc+→K-pπ+ 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 Λc+→KS0pπ0 decay. In our calculation, a sharp peaklike structure near 1665 MeV is predicted in the Λc+→K-pπ+ decay because of the interference effects between the Λ(1670) resonance and η-Λ loop channels. We also demonstrate that we can access direct information regarding the weak couplings of Λ(1670) and ς(1670) from the Λc+→KS0pπ0 decay. Finally, a possible interpretation for the 1665 MeV structure beyond our prediction is briefly discussed.