More about picture-changed vertices in superstring theory by Pettorino, R, Pezzella, F

“…We construct explicitly the lowest picture-changed vertex operators in superstring theory. We show, in particular, that the terms with (b, c) ghost number q=1 are of the form c(z) V(z) as the vertex operators in the bosonic string case.…”

Reparametrization ghost contribution to superstring multiloop amplitudes. by Pettorino, R, Pezzella, F

“…We use the sewing procedure in the operator formalism to construct the N-point g-loop vertex VN;g for the (b,c) system in superstring theory. After computing explicitly the lowest picture-changed states, we saturate VN;g with them showing that the reparametrization ghost contribution to g-loop superstring amplitudes is just the same as in bosonic string theory. © 1992 The American Physical Society.…”