Four Loop Scattering in the Nambu-Goto Theory

Understand

We initiate the study of multiloop scattering amplitudes in the Nambu-Goto theory on the worldsheet of a non-critical string.

• We start with a brute force calculation of two loop four particle scattering.
• Somewhat surprisingly, even though non-trivial UV counterterms are present at this order, on-shell amplitudes remain polynomial in the momenta of colliding particles.
• We show that this can be understood as a consequence of existence of certain close by (semi)integrable models.