Singlet structure function g_1 at small x and small Q^2

Explicit expressions for the singlet g_1 at small x and small Q^2 are obtained with the total resummation of the leading logarithmic contributions. It is shown that g_1 practically does not depend on Q^2 in this kinematic region. In contrast, it would be interesting to investigate its dependence on the invariant energy 2pq because, being g_1 positive at small 2pq, it can turn negative at greater values of this variable. The position of the turning point is sensitive to the ratio between the initial quark and gluon densities, so its experimental detection would enable to estimate this ratioComment: Section 2 is totally changed, one more ref adde

Impact of the running QCD coupling on the value of the intercept of the structure function g1g_1 singlet

The running QCD coupling effects for $g_1$ singlet are studied. We predict that asymptotically $g_1^S \sim x^{- \Delta_S}$, with the singlet intercept $\Delta_S \approx 0.85$.Comment: Talk given at the "XI International Workshop on Deep Inelastic Scattering (DIS2003)", Saint Petersburg, 23-27 April 2003; 6 page

Synthesis of DGLAP and total resummation of leading logarithms for the non-singlet spin structure function g_1

The explicit expressions for the non-singlet DIS structure function g_1 at small $x$ are obtained by resumming the leading logarithmic contributions. The role played by the fits for the initial parton densities currently used in the DGLAP on the small-x behavior of the non-singlet g_1 is discussed. Explicit expressions combining DGLAP with our results are presented.Comment: Talk given at XIII International Workshop on Deep Inelastic Scattering, April,27 - May,1, 2005, Madison, Wisconsin, USA, 3 pages, no figure

Small -x behavior of the non-singlet and singlet structure functions g_1

Explicit expressions for the non-singlet and singlet structure functions g_1 at the small $x$-region are obtained. They include the total resummation of double-logarithmic contributions and accounting for the running QCD coupling effects. We predict that both the non-singlet and singlet g_1 asymptotically ~ x^{- \Delta}, with the singlet intercept = 0.86 and being more than twice larger than the non-singlet intercept = 0.4. The impact of the initial quark and gluon densities on the sign of g_1 at x << 1 is discussed.Comment: Talk given at Xth Workshop on high energy spin physics, Dubna, Russia, September,16-20, 2003. LateX 9pp, 4 fig