Dong, YB (reprint author), Chinese Acad Sci, Inst High Energy Phys, POB 918-4, Beijing 100039, Peoples R China.
Pion cloud effects on Delta-N mass splitting are studied based on quark models. Pseudo-scalar pion-quark coupling is discussed in the relativistic and nonrelativistic frameworks. We separately calculate the pion cloud effects by the one-pion exchange potential and by another method which is consistent with the baryon chiral perturbation theory. Remarkable discrepancy in the mass splitting between the two methods is shown.