The relation between spin decomposition and topological structure of a nucleon is not yet fully understood. With the motivation to clarify their connection we study an exactly solvable toy model: large N QCD in (1+1) dimensions. Through bosonization this model is equivalent to the sine-Gordon model which admits topological kink as a classical solution. The kink is identified with a baryon and we demonstrate how to construct a quantum state corresponding to this solution. This allows us to evaluate the matrix element of axial current over the baryon state exactly in our model. We are able to single out the topological contribution to the baryon chirality. We observe that the non-trivial topology of the baryon state leads to an enhancement of the chirality distribution at small Bjorken x.
Nobuyuki Matsumoto