Speaker
Description
Understanding the decomposition of the nucleon spin into quark and gluon spin and orbital angular momentum is one of the key goals of the future Electron-Ion Collider (EIC). A proper decomposition of the nucleon angular momentum requires nonperturbative input. In this talk, we investigate the nonperturbative dynamical origin of the nucleon spin in
the QCD instanton vacuum and derive the corresponding effective operators. These operators are then implemented in an effective chiral theory, where the relevant QCD relations are preserved within the effective sector. In this setting, chiral interactions are expected to encode part of the nonperturbative dynamics relevant to the angular momentum decomposition. We then compute the quark spin, quark orbital angular momentum, and gluon spin contributions to the nucleon spin.