Zero Modes in Electromagnetic Form Factors of the Nucleon in a Light-Cone Diquark Model

Abstract

We use a diquark model of the nucleon to calculate the electromagnetic form factors of the nucleon described as a scalar and axialvector diquark bound state. We provide an analysis of the zero-mode contribution in the diquark model. We find there are zero-mode contributions to the form factors arising from the instantaneous part of the quark propagator, which cannot be neglected compared with the valence contribution but can be removed by the choice of wave function. We also find that the charge and magnetic radii and magnetic moment of the proton can be reproduced, while the magnetic moment of the neutron is too small. The dipole shape of the form factors, $G_M^p(Q^2)/{\mu }_p$ and $G_M^n(Q^2)/{\mu }_n,$ can be reproduced. The ratio $\mu G_E^p/G_M^p$ decreases with $Q^2,$ but too fast.

22 pages, 6 pages, accepted by J.Phys. G

References in corpus (8)

• Big Bang Nucleosynthesis (in "The Review of Particle Properties" 2004)
• On the rms-radius of the proton
• Updated dispersion-theoretical analysis of the nucleon electromagnetic form factors
• Consistent treatment of spin-1 mesons in the light-front formalism
• Electromagnetic form factor of the pion in the space- and time-like regions within the front-form dynamics
• Transition Form Factors between Pseudoscalar and Vector Mesons in Light-Front Dynamics
• Charge Form Factors of Quark-Model Pions II
• The Light-Front Zero-Mode Contribution to the Good Current in Weak Transition

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• Covariant analysis of electromagnetic current on the light cone: exposition with scalar Yukawa theory