Interpretation of High Energy String Scattering in terms of String   Configurations
  High energy string scattering at fixed momentum transfer, known to be dominated by Regge trajectory exchange, is interpreted by identifying families of string states which induce each type of trajectory exchange. These include the usual leading trajectory $\alpha(t)=\alpha^\prime t+1$ and its daughters as well as the ``sister'' trajectories $\alpha_m(t)=\alpha(t)/m-(m-1)/2$ and their daughters. The contribution of the sister $\alpha_m$ to high energy scattering is dominated by string excitations in the $m^{th}$ mode. Thus, at large $-t$, string scattering is dominated by wee partons, consistently with a picture of string as an infinitely composite system of ``constituents'' which carry zero energy and momentum. 
Steven L. Carbon and Charles B. Thorn