Poincare-invariant spectator-model currents for electroweak nucleon form factors

Abstract

The relativistic constituent quark model of low-energy quantum chromodynamics is found to yield a consistent picture of the electroweak structure of the nucleons. Notably, the electromagnetic and axial form factors of both the proton and the neutron can be described in close agreement with existing experimental data in the domain of low to moderate momentum transfers. For the theory it is mandatory to respect Poincare invariance and to fulfill additional conditions like charge normalization. Here we present covariant predictions of the one-gluon-exchange and Goldstone-boson-exchange constituent quark models for the electroweak form factors of the nucleons and give a critical discussion of the results in view of the point-form spectator model employed for the electromagnetic and axial current operators.