On a Possibility to Determine the Sign of the Polarized Gluon Distribution

Abstract

We investigate the possibility to draw conclusions on the sign of the spin-dependent gluon distribution, $\hat{I}”G(x,Q^2)$, from existing polarized DIS data. The spin-dependent parton distributions $\hat{I}”u_v,\hat{I}”d_v,\hat{I}”\bar{u},\hat{I}”\bar{d},\hat{I}”s$, and $\hat{I}”G$ are constructed in the framework of a phenomenological procedure taking into account some assumptions on signs of valence and sea parton distributions motivated by 't Hooft's mechanism of quark-quark interaction induced by instantons. The axial gluon anomaly and data on integral quark contributions to the proton spin, $\hat{I}”\tilde{u},\hat{I}”\tilde{d}$, and $\hat{I}”\tilde{s}$, are also taken into account. Predictions for the $x$- and $Q^2$-dependencies of the polarized proton and neutron structure functions, $g_1^p$ and $g_1^n$, are compared to experimental data. It is shown that the neutron structure function, $g_1^n$, is especially sensitive to the sign of $\hat{I}”G(x,Q^2)$. The results of our analysis supports the conclusion that this sign should be positive.

14 pages, latex, 12 figures