Proton charge radius extraction from electron scattering data using dispersively improved chiral effective field theory

Understand

We extract the proton charge radius from the elastic form factor (FF) data using a novel theoretical framework combining chiral effective field theory and dispersion analysis.

• Complex analyticity in the momentum transfer correlates the behavior of the spacelike FF at finite $Q^2$ with the derivative at $Q^2 = 0$.
• The FF calculated in the predictive theory contains the radius as a free parameter.
• We determine its value by comparing the predictions with a descriptive global fit of the spacelike FF data, taking into account the theoretical and experimental uncertainties.