A self-consistent value of the electric radius of the proton from the Lamb shift in muonic hydrogen

TL;DR

This paper derives a self-consistent, model-independent value for the proton's electric radius using high-precision Lamb shift measurements in muonic hydrogen, addressing higher-order proton-structure effects.

Contribution

It introduces a model-independent approach to evaluate higher-order proton size effects, leading to a new, consistent proton charge radius value from muonic hydrogen data.

Findings

Re-evaluated proton radius: 0.84022(56) fm

Resolved inconsistencies with previous models and data

Provided a more accurate proton charge radius estimate

Abstract

Recently a high-precision measurement of the Lamb shift in muonic hydrogen has been performed. An accurate value of the proton charge radius can be extracted from this datum with a high accuracy. To do that a sufficient accuracy should be achieved also on the theoretical side, including an appropriate treatment of higher-order proton-structure effects. Here we consider a higher-order contribution of the finite size of the proton to the Lamb shift in muonic hydrogen. Only model-dependent results for this correction have been known up to date. Meantime, the involved models are not consistent either with the existing experimental data on the electron-proton scattering or with the value for the electric charge radius of the proton extracted from the Lamb shift in muonic hydrogen. We consider the higher-order contribution of the proton finite size in a model-independent way and eventually derive a self-consistent value of the electric radius of the proton. The re-evaluated value of the proton charge radius is found to be R_E=0.84022(56) fm.