Electromagnetic form factors of the nucleon in relativistic baryon chiral perturbation theory

الأصل · EN

The electromagnetic form factors of the nucleon are calculated at order q⁴ in the relativistic formulation of baryon chiral perturbation theory. In order to obtain a consistent power counting for the renormalized diagrams we make use of the extended on-mass-shell renormalization scheme which we have discussed in a recent paper. We analyze the Dirac and Pauli form factors, F₁ and F₂, as well as the electric and magnetic Sachs form factors, Gₑ and Gₘ. Our results are compared with those obtained in the heavy-baryon approach and in the (relativistic) infrared regularization. In addition, the Sachs form factors are compared with experimental data. We confirm previous findings that a one-loop calculation of the electromagnetic form factors does not generate sufficient curvature for the Sachs form factors Gᵖₑ, Gᵖₘ, and Gⁿₘ. Moreover, the electric form factor of the neutron is very sensitive to higher-order contributions.