Nucleon spin structure functions, considering target mass correction, and higher twist effects at the NNLO accuracy and their transverse momentum dependence

Abstract

Using recent and updated world data on polarized structure functions ${g}_{1}$ and ${g}_{2}$ we perform an analysis based on quantum chromodynamics (QCD) as a theory of strong interactions at next-next-to-leading-order accuracy. We include also target mass corrections and higher twist effects to get more precise results in our fitting procedure. To confirm the validity of our fitting results several sum rules are examined and we do a comparison for them with results from other models. In our analysis we employ the Jacobi polynomials approach to obtain analytical solutions of the Dokshitzer-Gribov-LipatovAltarelli-Parisi evolution equations for parton distribution functions (PDFs). Using the extracted PDFs from our data analysis as input, we also compute the $x$- and ${\mathbf{p}}_{T}$-dependence of some transverse momentum dependence PDFs in polarized case, based on covariant parton model. These functions are naively even time-reversal at twist-two approximation. The results for transverse momentum dependences indicate proper and acceptable behavior with respect to what are presented in other literatures.