Multiloop Amplitudes of Light-cone Gauge NSR String Field Theory in Noncritical Dimensions

Understand

Feynman amplitudes of light-cone gauge superstring field theory are ill-defined because of various divergences.

• In a previous paper, one of the authors showed that taking the worldsheet theory to be the one in a linear dilaton background $\Phi=-iQX^{1}$ with Feynman $i\varepsilon$ $(\varepsilon>0)$ and $Q^{2}>10$ yields finite amplitudes.
• In this paper, we apply this worldsheet theory to dimensional regularization of the light-cone gauge NSR superstring field theory.
• We concentrate on the amplitudes for even spin structure with external lines in the (NS,NS) sector.