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Integral equation for spin dependent unintegrated parton distributions incorporating double ln^2(1/x) effects at low x

Jan Kwiecinski·Martin Maul
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Abstract

In this paper we derive an integral equation for the evolution of unintegrated (longitudinally) polarized quark and gluon parton distributions. The conventional CCFM framework is extended at small x in order to incorporate the QCD expectations concerning the double ln^2(1/x) resummation at low x for the integrated distributions. Complete Altarelli-Parisi splitting functions are included, that makes the formalism compatible with the LO Altarelli-Parisi evolution at large and moderately small values of x. The obtained modified polarized CCFM equation is shown to be partially diagonalized by the Fourier-Bessel transform. Results of the numerical solution for this modified CCFM equation for the non-singlet quark distributions are presented.

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Jan Kwiecinski, Martin Maul. 2003-01-19. Integral equation for spin dependent unintegrated parton distributions incorporating double ln^2(1/x) effects at low x. https://doi.org/10.1103/physrevd.67.034014

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