Two-nucleon electromagnetic current in chiral effective field theory:   one-pion exchange and short-range contributions
  We derive the leading one-loop contribution to the one-pion exchange and short-range two-nucleon electromagnetic current operator in the framework of chiral effective field theory. The derivation is carried out using the method of unitary transformation. Explicit results for the current and charge densities are given in momentum and coordinate space. 
S. Koelling, E. Epelbaum, H. Krebs and U.-G. Mei{\ss}ner
nucl-th