Anomalous quark chromomagnetic moment induced by instantons

It is shown that the instanton-induced quark–gluon interaction leads to the quark anomalous chromomagnetic moment. In the instanton-liquid model for the QCD vacuum, the chromomagnetic moment is μa=−πf/2αs, where f is the packing fraction of instantons in the vacuum. A new mechanism for single spin asymmetries in strong interaction based on instanton-induced chromomagnetic quark-gluon interaction is proposed.