Chiral Corrections to Lattice Calculations of Charge Radii
  Logarithmic divergences in pion and proton charge radii associated with chiral loops are investigated to assess systematic uncertainties in current lattice determinations of charge radii. The chiral corrections offer a possible solution to the long standing problem of why present lattice calculations yield proton and pion radii which are similar in size. 
Derek B. Leinweber and Thomas D. Cohen