Conformal higher-spin symmetries in twistor string theory

It is shown that similarly to massless superparticle, classical global symmetry of the Berkovits twistor string action is infinite-dimensional. We identify its superalgebra, whose finite-dimensional subalgebra contains psl(4|4,R)psl(4|4,R) superalgebra. In quantum theory this infinite-dimensional symmetry breaks down to SL(4|4,R)SL(4|4,R) one.