Yangian in the Twistor String

Understand

We study symmetries of the quantized open twistor string.

• In addition to global PSL(4|4) symmetry, we find non-local conserved currents.
• The associated non-local charges lead to Ward identities which show that these charges annihilate the string gluon tree amplitudes, and have the same form as symmetries of amplitudes in N=4 super conformal Yang Mills theory.
• We describe how states of the open twistor string form a realization of the PSL(4|4) Yangian superalgebra.