Existence of IR SCFT for SO(N) with one antisymmetric (adjoint) tensor and Nf vectors

Prove that the four-dimensional N=1 SO(N) gauge theory with one rank-2 antisymmetric tensor A (the adjoint of SO(N)) and Nf vector (fundamental) chiral multiplets Q (with superpotential W=0) flows to an interacting superconformal field theory in the infrared for all integers N and Nf satisfying 1 \le Nf \le 2N−4.

Background

This SO(N) Type I theory corresponds to adjoint SQCD. The authors’ a-maximization indicates unitary central charges and consistent behavior across the window (excluding Nf=0, which is N=2 SYM in a Coulomb phase), leading to a conjecture of an interacting IR SCFT.

Type I theories can have decoupled operators; here the flow remains well-behaved within the proposed window.

References

We therefore conjecture that this theory flows to an interacting SCFT for $1\leq N_f \leq 2N-4$.

— Large N Universality of 4d N=1 SCFTs with Simple Gauge Groups (2510.19136 - Cho et al., 21 Oct 2025) in Section 5.2 (1 A + Nf Q), Conformal window