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

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, $r_E=(0.838_{-0.004}^{+0.005}{}_{-0.003}^{+0.004})$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.

Comments: 8 pages, 2 figures, more discussions and references added, version accepted for publication in Physics Letters B