MAGNETIC AND AXIAL-VECTOR FORM-FACTORS AS PROBES OF ORBITAL ANGULAR-MOMENTUM IN THE PROTON - ART. NO. 033002

We have recently examined the static properties of the baryon octet (m agnetic moments and axial vector coupling constants) in a generalized quark model in which the angular momentum of a polarized nucleon is pa rtly spin [S-z] and partly orbital [L-z]. The orbital momentum was rep resented by the rotation of a flux tube connecting the three constitue nt quarks. The best fit is obtained with [S-z] = 0.08+/-0.15, [L-z] = 0.42+/-0.14. We now consider the consequences of this idea for the q(2 ) dependence of the magnetic and axial vector form factors. It is foun d that the isovector magnetic form factor G(M)(isovec)(q(2)) differs i n shape from the axial form factor F-A(q(2)) by an amount that depends on the spatial distribution of orbital angular momentum. The model of a rigidly rotating flux tube leads to a relation between the magnetic , axial vector and matter radii, [r(2)](mag) = f(spin)[r(2)](axial) 5/2f(orb)[r(2)](matt), where f(orb)/f(spin) = 1/3[L-z]/G(A), f(spin) f(orb) = 1. The shape of F-A(q(2)) is found to be close to a dipole w ith M-A = 0.92+/-0.06 GeV. [S0556-2821(98)03415-8]