A Field Theoretic Investigation of Spin in QCD

Utilizing the kinematical boost in light-front formalism one can address the issue of relativistic spin operators in an arbitrary reference frame. In the gauge $A^+=0$, the interaction dependent transverse spin operators can be separated into three parts. In analogy with the helicity sum rule, we propose a transverse spin sum rule. We perform a one loop renormalization of the transverse spin operator and show that the counterterm needed is the same as the linear mass counterterm in the light-front QCD Hamiltonian.