A systematic study of nucleon form factors with the pion cloud effect

Abstract In this study, the electromagnetic and gravitational form factors of the nucleon are studied simultaneously using a covariant quark–diquark approach, and the pion cloud effect on the form factors is explicitly discussed. The electromagnetic form factors are calculated to determine the parameters of our approach, and the gravitational form factors of the nucleon are then evaluated with these parameters. The electromagnetic and mechanical properties including charge radii, magnetic moments, and mass radii are presented. The D-term, which is believed to be connected with the internal force inside the nucleon, is also discussed. Our results are in reasonable agreement qualitatively with the experimental and lattice results, and suggest that the pion cloud contribution plays an indispensable role in our model, especially for the magnetic moments and the sign of the D-term.