Hyperon production in Λc+→K?pπ+ and Λc+→KS0pπ0

摘要

We investigate S = ? 1 hyperon production from the Λ c + → K ? p π + and Λ c + → K S 0 p π 0 decays within the effective Lagrangian approach. We consider the Σ / Λ ground states, Λ ( 1520 ) , Λ ( 1670 ) ( J p = 1 / 2 ? ) , Λ ( 1890 ) ( J p = 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 ( d 2 Γ / d M K ? p d M K ? π + ) for the Λ c + → K ? p π + 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 Λ c + → K S 0 p π 0 decay. In our calculation, a sharp peaklike structure near 1665?MeV is predicted in the Λ c + → K ? p π + 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 Λ c + → K S 0 p π 0 decay. Finally, a possible interpretation for the 1665?MeV structure beyond our prediction is briefly discussed.