Quark Spin Properties at High x

Abstract

A general three quark bound state satisfying the Pauli principle, and conserving angular momentum and isospin, is used to investigate the spin structure of nucleons at high $x$. It is shown if {$F_{1n}/F_{1p}$$\to$1/4}, then both $A_{1p}$ and $A_{1n}$, as well as quark spin distribution $\Delta u/u$, will approach 1 as $x$$\to$1 in polarized deep inelastic scattering. The spin distribution $\Delta d/d$ does not approach 1, but is bound by the limits $-1/3\le \Delta d/d\le 0$ for any $x$.

Comments: The quark function \phi(123) satisfies the constraint \phi(123)+\phi(213)=\phi(132)+\phi(231), which is less restrictive than the symmetry condition \phi(123)=\phi(132) originally stated. This means the constraint d\downarrow=u\uparrow does not hold at all x. (It still applies for x--> 1.) The main conclusions that \Delta u/u--> 1 as x--> 1, but -1/3<(Delta d/d)<0 still hold