Mechanism to cancel remaining higher-derivative divergences in NR bosonic alpha'-corrections

Establish a mechanism to cancel the remaining higher-derivative divergences at the four-derivative level in the non-relativistic bosonic string supergravity corrections.

Background

The authors highlight the utility of their covariant NR formalism for organizing finite contributions to four-derivative bosonic Lagrangians. However, they note that divergences persist at the higher-derivative level and that a cancellation mechanism is not yet known.

This identifies a broader unresolved issue beyond the specific Metsaev–Tseytlin terms: finding a general mechanism to cancel higher-derivative divergences in non-relativistic bosonic alpha'-corrections.