A New Approach to Superstring Field Theory

I review the construction of an action for open superstring field theory which does not suffer from the contact term problems of other approaches. I also discuss a possible generalization of this action for closed superstring field theory. (Talk presented at 32 Ahrenshoop International Symposium on Elementary Particle Theory in Buckow, Germany) 1 Problems with Conventional Approach The construction of a field theory action for the superstring is an important problem since it may lead to information about non-perturbative superstring theory which is unobtainable from the on-shell perturbative S-matrix. This information might be useful for understanding the nonperturbative dualities of the superstring. Although there was much activity ten years ago concerning a field theory action for the bosonic string, there was not much progress on constructing a field theory action for the superstring. For reasons described below, there was no obvious generalization of the bosonic string field theory action to the superstring. Since the non-perturbative dualities of the superstring are not expected to have any analog for the bosonic string, it is not too surprising that not much was learned about these dualities by studying bosonic string field theory. The covariant string field theory action for the bosonic string is based on a BRST operator Q and a string field A. In Witten’s approach to open string field theory, the gauge-invariant action is [1] Sopen = ∫ [AQA+ A] (1)