Proton spin structure and valence quarks

Abstract

The spin structure of the system of quasifree fermions having total angular momentum $J=1/2$ is studied in a consistently covariant approach. Within this model the relations between the spin functions are obtained. Their particular cases are the sum rules Wanzura - Wilczek, Efremov - Leader - Teryaev, Burkhardt - Cottingham and also the expression for the Wanzura - Wilczek twist 2 term $g_2^{WW}$. With the use of the proton valence quark distributions as an input, the corresponding spin functions are obtained. The resulting structure functions $g_1$ and $g_2$ are well compatible with the experimental data.

Comments: 20 pages, Tex, 2 figures (eps format). Minor language corrections are done in the revised version. Accepted for publication in Phys. Rev. D