The gravitational form factors are related to the matrix elements of the energy-momentum tensor $T^{mu u}$. Using the light front wave functions of the scalar quark-diquark model for nucleon predicted by the soft-wall AdS/QCD, we calculate the flavor
dependent $A(Q^2)$, $B(Q^2)$ and $bar{C}(Q^2)$ form factors. We also present all the matrix element of the energy-momentum tensor in a transversely polarized state. Further, we evaluate the matrix element of Pauli-Lubanski operator in this model and show that the intrinsic spin sum rule involves the form factor $bar{C}$. The longitudinal momentum densities in the transverse impact parameter space are also discussed for both unpolarized and transversely polarized nucleons.
Using a model calculation of dihadron fragmentation functions, we fit the spin asymmetry recently extracted by HERMES for the semi-inclusive pion pair production in deep-inelastic scattering on a transversely polarized proton target. By evolving the
obtained dihadron fragmentation functions, we make predictions for the correlation of the angular distributions of two pion pairs produced in electron-positron annihilations at BELLE kinematics. Our study shows that the combination of two-hadron inclusive deep-inelastic scattering and electron-positron annihilation measurements can provide a valid alternative to Collins effect for the extraction of the quark transversity distribution in the nucleon.
