Spinning particle, rotating black hole and twistor-string

Structure of spinning particle based on the rotating black hole solution is considered. It has gyromagnetic ratio $g=2$ and a nontrivial twistorial and stringy systems. The mass and spin appear from excitations of the Kerr circular string, while the Dirac equation describes excitations of an {\it axial} stringy system which is responsible for scattering. Complex Kerr geometry contains an open twistor-string, target space of which is equivalent to the Witten's `diagonal' of the $CP^3\times CP^{*3}$.