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, $ΔG(x, Q^2)$, from existing polarized DIS data. The spin-dependent parton distributions $Δu_v, Δd_v, Δ{\bar u}, Δ{\bar d}, Δ{s}$, and $ΔG$ 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, $Δ\tilde u, Δ\tilde d$, and $Δ\tilde s$, 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 $ΔG(x, Q^2)$. The results of our analysis supports the conclusion that this sign should be positive.