MODEL-BUILDING FOR FRACTIONAL SUPERSTRINGS

We investigate heterotic string-type model-building for the recently proposed fractional superstring theories. We concentrate on the cases with critical space-time dimensions four and six, and find that a correspondence can be drawn between the new fractional superstring models and a special subset of the traditional heterotic string models. This allows us to generate the partition functions of the new models, and demonstrate that their number is indeed relatively limited. It also appears that these strings have uniquely natural compactifications to lower dimensions. In particular, the D(c) = 6 fractional superstring has a natural interpretation in four-dimensional space-time.