High-precision determination of the electric and magnetic radius of the proton

TL;DR

This paper employs dispersion theory and recent scattering data to precisely determine the electric and magnetic radii of the proton, reducing uncertainties and improving accuracy over previous measurements.

Contribution

It introduces an improved dispersion analysis with a refined two-pion continuum description, leading to high-precision proton radius measurements.

Findings

Electric radius: 0.838 fm with small uncertainties

Magnetic radius: 0.847 fm with small uncertainties

Reduced systematic and statistical errors in radius determination

Abstract

Using dispersion theory with an improved description of the two-pion continuum based on the precise Roy-Steiner analysis of pion-nucleon scattering, we analyze recent data from electron-proton scattering. This allows for a high-precision determination of the electric and magnetic radius of the proton, $r_E = (0.838^{+0.005}_{-0.004}{}^{+0.004}_{-0.003})\,$fm and $r_M = (0.847\pm{0.004}\pm{0.004})\,$fm, where the first error refers to the fitting procedure using bootstrap and the data while the second one refers to the systematic uncertainty related to the underlying spectral functions.