Classical string profile for a class of DDF amplitudes

In the critical bosonic string theory, we explicitly evaluate the three point scattering amplitude at tree level, of a photon with two massive higher spins. The massive excitations belong to states of the form A − r 1 s 1 A − r 2 s 2 where A − n is a DDF creation operator. Next, we take the infinite “spin” limit to arrive at the classical string dynamics. We find a rotating “floppy” string lying mostly on a plane which develops a transverse kink.