Model independent analysis of proton structure for hydrogenic bound   states
  Proton structure effects in hydrogenic bound states are analyzed using nonrelativistic QED effective field theory. Implications for the Lamb shift in muonic hydrogen are discussed. Model-dependent assumptions in previous analyses are isolated, and sensitivity to poorly constrained hadronic structure in the two-photon exchange contribution is identified. 
Richard J. Hill and Gil Paz
hep-ph hep-ex nucl-ex nucl-th physics.atom-ph