Modeling the Partonic Structure of the Nucleon Through Semi-Inclusive Deep Inelastic Scattering*

The focus of this research is to model the transverse spin and momentum partonic structure of the nucleon. Using hard scattering processes such as semi-inclusive deep inelastic scattering (SIDIS) as a means to access this sub-structure it is evident that precise knowledge of the transverse degrees of freedom of partons (momentum and spin angular momentum) are essential to unfold a comprehensive description of the nucleon. Of particular importance are transverse momentum dependent parton distribution and fragmentation functions (TMD PDFs/FFs). By observing the experimental single-spin asymmetries of produced pions for a longitudinally polarized electron beam on an unpolarized nucleon we explore the spin-orbit correlations in the beam-spin asymmetry [1]. Considering these single-spin asymmetries we then model the twist-three TMD PDF, $g^\perp(x,\mathbf{k}_T)$. We also study the factorization of the SIDIS cross sections for twist-3 TMD PDFs [2] by studying the issue of light cone divergence in the quark-target model.\\[4pt] [1] M.~Aghasyan {\it et al.}, Phys. Lett B {\bf 704}, 397 (2011).\\[0pt] [2] L.~P.~Gamberg {\it et al.}, Phys. Lett B {\bf 639}, 508 (2006).