Pionic Fluctuations of Constituent Quarks
  Pion loop fluctuations of the constituent u and d quarks are shown to give only a minute contribution to the intrinsic charge radius of the neutron, under the assumption that the pion-quark coupling constant has its conventional value, with a cut-off scale of the order of 1.0 GeV. The contribution from the pion loops to the anomalous magnetic moment of the neutron represents a small ($\sim$ 12-14%) increase over of the static quark model value. 
L. Ya. Glozman, D. O. Riska