Extremal Correlator of Three Vertex Operators for Circular Winding   Strings in AdS5xS5
  We study a three-point correlator of the three heavy vertex operators representing the circular winding string states which are point-like in AdS_5 and rotating with two spins and two winding numbers in S^5. We restrict ourselves to the case that two of the three vertex operators are located at the same point. We evaluate semiclassically the specific three-point correlator on a stationary splitting string trajectory which is mapped to the complex plane with three punctures. It becomes an extremal and 4d conformal invariant three-point correlator on the boundary. The marginality condition of the vertex operator is discussed. 
Shijong Ryang
hep-th