The role of 5-quark components on the nucleon form factors Original Research Article

The covariant quark model is shown to allow a phenomenological description of the neutron electric form factor, View the MathML source, in the impulse approximation, provided that the wave function contains minor (∼3%) admixtures of the lowest energy sea-quark configurations. While that form factor is not very sensitive to whether the View the MathML source in the View the MathML source component is in the P-state or in the S-state, the calculated nucleon magnetic form factors are much closer to the empirical values in the case of the former configuration. In the case of the electric form factor of the proton, View the MathML source a zero appears in the impulse approximation close to 10 GeV2, when the View the MathML source is in the P-state. That configuration, which may be interpreted as a pion loop (“cloud”) fluctuation, also leads to a clearly better description of the nucleon magnetic moments. When the amplitude of the sea-quark admixtures are set so as to describe the electric form factor of the neutron, the View the MathML source admixtures have the phenomenologically desirable feature, that the electric form factor of the proton falls at a more rapid rate with momentum transfer than the magnetic form factor.