Colliding fields in two-dimensional dilaton gravity background

The (1+1)-dimensional dilatonic background geometry of [C. Callan, S. Giddings, J. Harvey and A. Strominger, Phys. Rev. D 45 (1992) R1005] admits an infinite class of colliding wave solutions. We give examples from real and ghost fields with bounded/unbounded profiles. In particular, colliding ghost fields in the "lineland" geometry create particle-like wormholes. Such wormholes, however, collapse to a black hole whenever the supporting ghosts turn off. Lastly, it is shown that the vacuum collision of null fields yields a ghost wormhole which is unstable.