Quark Angular Momentum and Gravitational Form Factors

We investigate the quark angular momentum in a light-cone spectator model. The canonical angular momentum sum rule is satisfied in both the scalar and the axial-vector cases. Then we perform a calculation of the gravitational form factors which are expected to be related to the angular momentum of each constituent in this no gauge field model. We find this relation is satisfied for the total angular momentum as a direct conclusion of the momentum fraction sum rule and the anomalous gravitomagnetic moment sum rule, but for each constituent it is violated.CPCI-S(ISTP)liutb@pku.edu.cn; mabq@pku.edu.cn4