EFFECTIVE ACTIONS FOR HETEROTIC STRING THEORY

Abstract

Heterotic String Theory is an attempt to construct a description of nature that is more satisfying than the Standard Model. A major problem is that it is very difficult to do explicit calculations in string theory. Therefore, it is useful to construct a ’normal’ field theory that approximates HST. The way to construct such a field theory is described briefly. The result is a perturbation expansion in some parameter α′. related to the inverse string tension. There are problems concerning the supersymmetrisation of the [Formula: see text] contribution. These may be caused by the assumption that the action can be written in terms of a local Lagrangian of the physical fields only.