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

TL;DR

This paper performs a high-precision QCD analysis of nucleon spin structure functions using NNLO accuracy, incorporating target mass corrections and higher twist effects, and explores their transverse momentum dependence.

Contribution

It introduces a comprehensive NNLO analysis including target mass and higher twist effects, employing Jacobi polynomials for analytical solutions and extending to TMD PDFs in polarized cases.

Findings

Validated sum rules with improved accuracy

Extracted polarized PDFs with target mass and higher twist corrections

Analyzed transverse momentum dependence of TMD PDFs

Abstract

Using recent and updated world data on polarized structure functions $g_1$ and $g_2$ we perform QCD analysis at the next-next-to-leading-order (NNLO) accuracy. We include also target mass correction and higher twist effect 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 Jacobi polynomials approach to obtain analytical solutions of the DGLAP 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 (TMD) PDFs in polarized case, based on covariant parton model. These functions are naively even time-reversal (T-even) at twist-2 approximation. The results for TMDs are indicating proper and acceptable behaviour with respect to what are presented in other literatures.