Comment on "Breakdown of the expansion of finite-size corrections to the hydrogen Lamb shift in moments of charge distribution"

TL;DR

This paper critiques a recent proposal to resolve the proton radius puzzle by modifying the proton's charge form factor, arguing that the proposed modifications are unphysical and do not effectively solve the puzzle.

Contribution

It provides a critical analysis showing that the proposed form factor modification is unphysical and does not resolve the proton radius puzzle.

Findings

The proposed form factor modification is unphysical.

Reducing the modification to physical levels does not solve the radius puzzle.

The critique challenges the viability of the proposed resolution.

Abstract

In a recent paper, Hagelstein and Pascalutsa examine the error associated with an expansion of proton structure corrections to the Lamb shift in terms of moments of the charge distribution. They propose a small modification to a conventional parameterization of the proton's charge form factor and show that this can resolve the proton radius puzzle. However, while the size of the "bump" they add to the form factor is small, it is large compared to the total proton structure effects in the initial parameterization, yielding a final form factor that is unphysical. Reducing their modification to the point where the resulting form factor is physical does not allow for a resolution of the radius puzzle.