Compute heterotic disk effects and settle the g_s scaling

Develop a first-principles framework to calculate heterotic disk contributions in the HO theory and ascertain the precise g_s^{-1} scaling of the corresponding heterotic (−1)-brane instanton action.

Background

After proposing that HO heterotic disks account for Shenker effects, the authors argue on physical grounds that the instanton action should scale as g_s^{-1}, but emphasize that this is not proven.

They state that resolving this requires tools to directly compute the effects of heterotic disk diagrams, which lie beyond the conventional worldsheet (B)CFT paradigm.