Polarized structure functions from AdS/CFT

We investigate deep inelastic and elastic scattering on a polarized spin-$\frac{1}{2}$ hadron using gauge/string duality. AdS/CFT correspondence provides us new insights into gauge theories in strong coupling regime. This spin-$\frac{1}{2}$ hadron corresponds to a supergravity mode of the dilatino. The polarized deep inelastic structure functions are computed in supergravity approximation at large t' Hooft coupling $\lambda$ and finite $x$ with $\lambda^{-1/2}\ll x<1$. Furthermore, we discuss the moments of all structure functions, and propose an interesting sum rule $\int_{0}^{1} \textrm{d}x g_2\left(x, q^2\right) =0$ for $g_2$ structure function which is known as the Burkhardt-Cottingham sum rule in QCD. In addition, we discuss the possible small-x contributions for $g_1$ due to the consideration of the angular momentum sum rule. In the end, the elastic scattering is studied and elastic form factors of the spin-$\frac{1}{2}$ hadron are calculated within the same framework.