Effective Field Theory Analysis of Proton Structure in Hydrogenic Bound States

This project performs new theoretical calculations relating atomic spectroscopy and lepton-nucleon scattering measurements in a model-independent way. These calculations will yield a model-independent determination of proton structure corrections to the Lamb shift and hyperfine splitting in hydrogen and muonic hydrogen, enabling the robust determination of fundamental constants including the Rydberg constant, and of universal nucleon structure parameters including the charge and magnetic radii of the proton. The project includes foundational developments in NRQED (nonrelativistic QED) effective field theory for composite particles, including extensions to nuclei of spin > 1/2 , and extensions to high orders in the 1/M expansion for applications to phenomenologically important nuclear structure corrections in simple atomic systems. Low energy constraints of NRQED will be combined with novel dispersive techniques to provide model independent predictions for a range of lepton-nucleon scattering observables that determine nucleon structure inputs to atomic physics, and to search for new particles and forces.