Evaluation of the proton charge radius from e-p scattering

Understand

In light of the proton radius puzzle, the discrepancy between measurements of the proton charge radius from muonic hydrogen and those from electronic hydrogen and electron-proton scattering measurements, we reexamine the charge radius extractions from electron scattering measurements.

• We provide a recommended value for the proton RMS charge radius, $r_E = 0.879 \pm 0.011$ fm, based on a global examination of elastic e-p scattering data.
• The uncertainties include contributions to account for tension between different data sets and inconsistencies between radii using different extraction procedures.