All-Order Coulomb Corrections to Delbruck Scattering above the Pair-Production Threshold

We report calculations of Delbruck scattering that include all-order Coulomb corrections for photon energies above the threshold of electron-positron pair creation. Our approach is based on the application of the Dirac-Coulomb Green's function and accounts for the interaction between the virtual electron-positron pair and the nucleus to all orders in the nuclear binding strength parameter & alpha;Z. Practical calculations are performed for the scattering of 2.754 MeV photons off plutonium atoms. We find that including the Coulomb corrections enhances the scattering cross section by up to 50% in this case. The obtained results resolve the long-standing discrepancy between experimental data and theoretical predictions and demonstrate that an accurate treatment of the Coulomb corrections is crucial for the interpretation of existing and guidance of future Delbruck scattering experiments on heavy atoms.

Automated summary

We present calculations of Delbruck scattering with all-order Coulomb corrections for photon energies above the electron-positron pair creation threshold. Our method utilizes the Dirac-Coulomb Green's function and accounts for the interaction between the virtual electron-positron pair and the nucleus to all orders in the nuclear binding strength parameter αZ. Practical calculations are performed for 2.754 MeV photon scattering off plutonium atoms. Our results show that including the Coulomb corrections increases the scattering cross section by up to 50% in this case, resolving the long-standing discrepancy between experimental data and theoretical predictions.