ND and NB systems in quark delocalization color screening model

The ND and NB systems with I = 0 and 1, J^P = (1)/(2)^±, (3)/(2)^±, and (5)/(2)^± are investigated within the framework of the quark delocalization color screening model. The results show that all the positive-parity states are unbound. By coupling to the ND* channel, the state ND with I = 0, J^P = (1)/(2)^- can form a bound state, which can be invoked to explain the observed Σ(2800) state. The mass of the ND* with I = 0, J^P = (3)/(2)^- is close to that of the reported Λ_c(2940)⁺, which indicates that Λ_c(2940)⁺ can be explained as a ND* molecular state in QDCSM. Besides, the ΔD* with I = 1, J^P = (5)/(2)^- is also a possible resonance state. The results of the bottom case of the NB system are similar to those of the ND system. Searching for these states will be a challenging subject of experiments. (orig.)