Role of N*(1535) in the Λ+c → K0ηp decay and the possible p state in the Λ+c → π0p decay

The nonleptonic weak decays of Λ⁺_c → K⁰ηp and Λ⁺_c → π⁰p are investigated from the viewpoint of probing the N*(1535) resonance and the possible p state. For the Λ⁺_c → K⁰ηp decay, we study the invariant mass distribution of ηp with both the chiral unitary approach and an effective Lagrangian model. Within the chiral unitary approach, the N*(1535) resonance is dynamically generated from the final state interaction of mesons and baryons in coupled channels. While for the effective Lagrangian model, we take a Breit-Wigner formula for the N*(1535) resonance. We found that the behavior of the N*(1535) resonance in the Λ⁺_c → K⁰N*(1535) → K⁰ηp decay within the two approaches is different. For the Λ⁺_c → π⁰p decay, we consider a triangle singularity mechanism, where the Λ⁺_c decays into the K*Σ*(1385), the Σ*(1385) decays into the π⁰Σ/Λ, and then the K*Σ/Λ merge to produce the p in the final state. This mechanism produces a peak structure around 2020 MeV. In addition, the possibility that there is a hidden-strange pentaquark-like state is also considered by taking into account the final state interactions of K*Λ, K*Σ, and p. We conclude that it is difficult to search for the hidden-strange state in this decay. However, we do expect nontrivial behavior in the p invariant mass distribution. The proposed Λ⁺_c decay mechanism here can provide valuable information on the properties of these nuclear resonances and can in principle be tested by experiments such as BESIII, LHCb and Belle-II.