Polarized DIS in N = 4 SYM: Where is spin at strong coupling?

Abstract

Using the AdS/CFT correspondence, we calculate the polarized structure functions in strongly coupled = 4 supersymmetric Yang-Mills theory deformed in the infrared. We find that the flavor singlet contribution to the g 1 structure function is vanishingly small, while the flavor non-singlet contribution shows the Regge behavior at small-x with an intercept slightly less than 1. We explicitly check that the latter satisfies the moment sum rule. We discuss the 'spin crisis' problem and suggest that at strong coupling the spin of a hadron entirely comes from the orbital angular momentum. © SISSA 2009.