Lower bound on the proton charge radius from electron scattering data

Franziska Hagelstein; Vladimir Pascalutsa

doi:10.1016/j.physletb.2019.134825

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arXiv · 1812.02028

Lower bound on the proton charge radius from electron scattering data

Franziska Hagelstein·Vladimir Pascalutsa

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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.

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Franziska Hagelstein, Vladimir Pascalutsa. 2019-03-25. Lower bound on the proton charge radius from electron scattering data. https://doi.org/10.1016/j.physletb.2019.134825

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