Effective description of the weakly bound state

Determine whether the very small binding energy of the bound state in three-dimensional Ising Field Theory implies a useful effective approximation.

Background

The numerical analysis finds a stable bound state whose mass is close to twice the lightest-particle mass, with an extrapolated ratio of approximately 1.96. The resulting small binding energy motivates the unresolved question of whether the bound state can be described by a controlled or otherwise useful effective approximation.