Theory Seminar   May 5


Impact of the total resummation of the leading logarithms on the small x behavior of the spin structure function g_1

Boris Ermolaev
Ioffe Phys. Tech. Inst.

Total resummation of the leading (double and single) logarithms converts the small-x behavior of g_1 into the Regge one in contrast to the DGLAP predictions. Accounting for the running coupling effects allows to estimate the intercepts of the non-singlet and singlet components of g_1 (0.4 and 0.8 approx) and also estimate the sign of the g_1 singlet at x<<1 (negative). Ther is a new scaling for g_1 at small x: g_1 depends on one argument (Q^2/x^2) instead of depending on two, x and Q^2. Contrary to the common opinion, we find that the impact of the resummation is quite sizable for the values of x = 0.005 approx and less. DGLAP formally does not account for those contributions but actually imitates them through using the singular fits for the parton densities. -

 Directions  to Fermilab.
Keith Ellis, and Ayres Freitas,

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