We investigate the dilaton vertex operator in the covariant formulation of strings. We find that the Faddeev-Popov ghosts play an essential role to construct conformal fields. © 1987.
Terao, H., & Uehara, S. (1987). On the dilaton vertex in the covariant formulation of strings. Physics Letters B, 188(2), 198–202. https://doi.org/10.1016/0370-2693(87)90006-2