Proton Electromagnetic Form Factor Ratios at Low Q^2

Abstract

We study the ratio $R\equiv \mu G_E(Q^2)/G_M(Q^2)$ of the proton at very small values of $Q^2$. Radii commonly associated with these form factors are not moments of charge or magnetization densities. We show that the form factor $F_2$ is correctly interpretable as the two-dimensional Fourier transformation of a magnetization density. A relationship between the measurable ratio and moments of true charge and magnetization densities is derived. We find that existing measurements show that the magnetization density extends further than the charge density, in contrast with expectations based on the measured reduction of $R$ as $Q^2$ increases.

4 pages 3 figures We have corrected references, figures and some typographical errors

References in corpus (4)

• Global analysis of proton elastic form factor data with two-photon exchange corrections
• Empirical transverse charge densities in the nucleon and the nucleon-to-$\Delta$ transition
• Precise determination of low-Q nucleon electromagnetic form factors and their impact on parity-violating e-p elastic scattering
• Electroweak structure of the nucleon, meson cloud and light-cone wavefunctions

Cited by in corpus (1)

• The neutron negative central charge density: an inclusive-exclusive connection