Related papers: Transverse Force on Transversely Polarized Quarks …
The interaction dependent part of the $x^2$-moment of the twist-3 polarized parton distribution $g_2(x)$ is related to the transverse force acting on the active quark in deep-inelastic scattering off a transversely polarized nucleon…
Generalized Parton Distributions (GPDs) provide information on the distribution of quarks in impact paarmeter space. For transversely polarized nucleons, these impact parameter distributions are transversely distorted and this deviation…
The twist-3 transverse spin--dependent nucleon structure function $g_2$ arises in high-energy processes involving a transversely polarized nucleon. Its connection to quark--gluon correlations allows for an interpretation in terms of the…
Impact parameter dependent parton distributions are transversely distorted when one considers transversely polarized nucleons and/or quarks. This provides a physical mechanism for the T-odd Sivers effect in semi-inclusive deep-inelastic…
Polarized structure functions at low $Q^2$ have the physical interpretation of (generalized) spin polarizabilities. At high $Q^2$, the polarized parton distribution $g_2(x)$ provides access to quark-gluon correlations in the nucleon. We…
Using the equations of motion of QCD and Lorentz invariance relations, we show a new, more direct way of obtaining the decomposition of the proton's quark transverse angular momentum into its spin and orbital components. The new…
The present status of the longitudinal polarized parton densities (PDFs) and the contribution of their first moments to the nucleon spin is discussed. Special attention is paid to the role of higher twist effects in determining the PDFs and…
The quark-parton model calculation including the effects of intrinsic transverse momentum and of all six twist-two distribution functions of quarks in polarized nucleons is performed. It is demonstrated that new twist-two quark distribution…
We derive a new twist-3 partonic sum rule for the transverse spin of the proton, which involves the well-know quark spin structure function $g_T(x)=g_1(x)+g_2(x)$, the less-studied but known transverse gluon polarization density $\Delta…
We study the transverse polarization of hyperons produced in semi-inclusive deep inelastic scattering, $ep\to e\Lambda^\uparrow X$, in the framework of the collinear twist-3 factorization. The cross section from the twist-3 distribution…
We compute the quark and gluon transverse momentum dependent parton distribution functions at next-to-next-to-next-to-leading order (N$^3$LO) in perturbative QCD. Our calculation is based on an expansion of the differential Higgs boson and…
The higher twist T-even transverse momentum dependent distribution (TMD) $h_3(x, {\bf p_\perp^2})$ for the proton has been examined in the light-front quark-diquark model (LFQDM). By deciphering the unintegrated quark-quark correlator for…
We investigate the chiral-even twist-3 generalized parton distributions (GPDs) of valence quarks in the proton at nonzero skewness $\xi$, using a spectator model with scalar and axial-vector diquarks. We consider the exponential form factor…
It is shown that the azimuthal dependence of the distribution of hadrons in a quark jet is a probe of the transverse spin of the quark initiating the jet. This results in a new spin-dependent fragmentation function that acts at the twist-2…
We have dealt with the twist-4 T-even transverse momentum-dependent parton distributions (TMDs) for the case of proton in the light-front quark-diquark model (LFQDM). By decoding the unintegrated quark-quark correlator for the…
We derive relations between polarized transverse momentum dependent distribution functions (TMDs) and the usual parton distribution functions (PDFs) in the 3D covariant parton model, which follow from Lorentz invariance and the assumption…
We study semi-inclusive DIS with a transversely polarized target in the approach of collinear factorization. The effects related with the transverse polarization are at twist-3. We derive the complete result of twist-3 contributions to the…
We initiate the study of transverse momentum-dependent (TMD) fragmentation functions for heavy quarks, demonstrate their factorization in terms of novel nonperturbative matrix elements in heavy-quark effective theory (HQET), and prove new…
Tensor-polarized twist-3 parton distribution functions (PDFs) $f_{LT}(x)$ are calculated for the spin-1 deuteron by using twist-2 relations, which are similar to the Wandzura-Wilczek relation and the Burkhardt-Cottingham sum rule in the…
Transverse momentum dependent parton distribution functions (TMDPDFs) encode information about the intrinsic motion of quarks inside the nucleon. They are important non-perturbative ingredients in our understanding of, e.g., azimuthal…