Comment on Transverse Charge Density and the Radius of the Proton

TL;DR

This paper critiques a novel method for determining the proton charge radius that avoids slope extrapolation, showing that results are highly sensitive to data binning and additional data inclusion, leading to conflicting conclusions.

Contribution

The paper highlights issues with a new proton radius measurement method, demonstrating its results depend heavily on data handling choices.

Findings

Results vary significantly with data binning.

Including additional data alters the radius estimate.

The method's reliability is questionable due to sensitivity.

Abstract

The charge radius of the proton is typically determined from electron-proton scattering by extracting the proton's electric form factor and then making use of the derivative of that form factor at zero four-momentum transfer. Unfortunately, experimentally, one cannot measure to zero four-momentum transfer and thus extrapolation is often required. In the work of Alexander Gramolin and Rebecca Russell, they present a novel method that does not use the slope and found a radius of the proton that contradicts many other recent results. Our analysis of their paper discusses some issues with this method and we show that by simply changing the binning of the data and/or including an additional set of data the results change dramatically.