Off-mass-shell dual amplitudes without ghosts

A new approach to the construction of off-shell dual amplitudes and hadronic currents is presented. The guiding principle in this work is the manifest incorporation of the Virasoro gauge conditions. This requirement is so stringent that we are only able to find a solution for a particular dimension of spacetime: 16 in the case of an off-shell scalar in the Veneziano model. Furthermore, the amplitude for one off-shell state and an arbitrary number of on-shell states turns out to be given by a logarithmically divergent integral, although it is quite well-behaved in all other respects. It is suggested that the divergence problem might not occur for a ghost-free model with α(0) < 1, and that suitable modification of the model can bring the dimension selected by the currents into coincidence with the critical dimension. These requirements could lead a long way toward determining a unique model.