Anomalous Quark Chromomagnetic Moment Induced by Instantons
  It is shown that the quark-gluon interaction induced by instantons leads to the quark anomalous chromomagnetic moment. In the instanton-liquid model for the QCD vacuum, the chromomagnetic moment is $\mu_a=-\frac{\pi f}{2\alpha_s}$, where f is the packing fraction of instantons in the vacuum. 
N.I. Kochelev, (JINR, Dubna)