Nucleon spin-averaged forward virtual Compton tensor at large Q2

The nucleon spin-averaged forward virtual Compton tensor determines important physical quantities such as electromagnetically induced mass differences of nucleons and two-photon exchange contributions in hydrogen spectroscopy. It depends on two kinematic variables: nu, the virtual photon energy in the proton rest frame, and Q(2), the photon's invariant four-momentum squared. Using the operator product expansion, we calculate the tensor's large-Q(2) behavior for nu = 0, including for the first time the full spin-2 contribution and correcting a previous result in the literature for the spin-0 contribution. Implications for the proton radius puzzle are discussed.