ar X iv : h ep - t h / 06 02 05 6 v 1 6 F eb 2 00 6 Indecomposable Representations in n Symmetric b , c Ghost Systems via Deformations of the Virasoro Field

The Virasoro field associated to b, c ghost systems with arbitrary integer spin λ on an n-sheeted branched covering of the Riemann sphere is deformed. This leads to reducible but indecomposable representations, if the new Virasoro field acts on the space of states, enlarged by taking the tensor product over the different sheets of the surface. For λ = 1, proven LCFT structures are made explicit through this deformation. In the other cases, the existence of Jordan cells is ruled out in favour of a novel kind of indecomposable representations.