Gluon contribution to the angular momentum distribution of a dressed quark state (2411.18076v1)

Abstract: We compute the contribution of the gluonic component of the energy-momentum tensor (EMT) to the angular momentum density in various decompositions. We use the light-front Hamiltonian technique, and a two-component formalism in light-front gauge, where the constrained degrees of freedom are eliminated. Instead of a nucleon, we consider a simple composite spin-$1/2$ state, namely a quark dressed with a gluon. We present two dimensional light-front distributions in transverse impact parameter space, and compare the different angular momentum decompositions at the density level. Incorporating also the contribution coming from the quark part of the EMT, we verify the spin sum rule for such a state.