Spin-Dependent Structure Functions of the Photon

Abstract

The implications of the positivity constraint on the presently unknown polarized structure function of the photon, $g_1^{\gamma }(x,Q^2)$, are studied in detail. In particular the non-trivial consequences of this constraint, $|g_1^{\gamma }(x,Q^2)|\le F_1^{\gamma }(x,Q^2)$, in the next-to-leading order analysis of $g_1^{\gamma }$ are pointed out by employing appropriate (DIS) factorization schemes related to $g_1^{\gamma }$ and $F_1^{\gamma }$ (rather than to $F_2^{\gamma }$).

Comments: 15 pages, LaTeX, 4 figures