Holomorphic strong-coupling scale (${\Lambda }^{b_0}$)

The holomorphic strong-coupling scale packages the gauge coupling and theta angle into ${\Lambda }^{b_0}$. Treating it as a spurion under anomalous chiral symmetries strongly constrains nonperturbative superpotentials and moduli-space deformations.

For SQCD with $N_f<N_c$, strong dynamics generates the Affleck–Dine–Seiberg superpotential. For $SU(2)$ with one flavor it is proportional to ${\Lambda }^5/M$ and produces a runaway to infinite meson expectation value.