Novel determination of the nucleon form factors and the proton radius with dispersively improved chiral EFT

Abstract

We present a new method to determine the electromagnetic form factors by combining ingredients from dispersion theory with the standard chiral calculations. We show that with this approach one can determine the electromagnetic form factors of the nucleon up to energies of Q2 ≤ 2 GeV2. The results can be applied to determine que proton charge radius from the current low Q2 data (Q2 ≤ 0.5 GeV2) without the need of any extrapolation to Q2 = 0. The extracted value, rEp=0.844(7) fm, is in good agreement with the muonic hydrogen spectroscopy result.