Lower bound on the proton charge radius from electron scattering data

Abstract

The proton charge-radius determinations from the electromagnetic form-factor measurements in electron-proton scattering require an extrapolation to zero momentum transfer ($Q^2=0$) which is prone to model-dependent assumptions. We show that the data at finite momentum transfer can be used to establish a rigorous lower bound on the proton charge radius. Using the available $ep$ data at low $Q^2$, we obtain $R_E>0.850(1)$ fm as the lower bound on the proton radius. This reaffirms the discrepancy between the $ep$ and muonic-hydrogen values, while bypassing the model-dependent assumptions that go into the fitting and extrapolation of the $ep$ data.

8 pages, 4 figures, 1 table; new analysis (figure 4) added, text revised accordingly, typos corrected

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Cited by in corpus (6)

• The proton charge radius
• How Analytic Choices Can Affect the Extraction of Electromagnetic Form Factors from Elastic Electron Scattering Cross Section Data
• Transverse charge density and the radius of the proton
• Properties of the Sachs electric form factor of the proton on the basis of recent $e-p$ scattering experiments and hydrogen spectroscopy
• Note on the electromagnetic radius of proton
• Comparison of results for the electromagnetic form factors of the proton at low $Q^2$