Existence of IR SCFT for Sp(N) with one symmetric tensor and 2Nf fundamentals

Prove that the four-dimensional N=1 Sp(N) gauge theory with one rank-2 symmetric tensor S and 2Nf fundamental chiral multiplets Q (with superpotential W=0 and even number of fundamentals due to the Witten anomaly) flows to an interacting superconformal field theory in the infrared for all integers N and Nf satisfying 1 \le Nf \le 2N+2.

Background

This Sp(N) Type I model includes a symmetric tensor and an even number of fundamentals. Excluding Nf=0 (which gives N=2 SYM in a Coulomb phase), the authors find well-behaved a-maximization and unitary central charges, leading to a conjecture of an interacting IR SCFT.

Type I theories often have decoupled operators; within the stated window, the flow appears consistent.

References

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

— Large N Universality of 4d N=1 SCFTs with Simple Gauge Groups (2510.19136 - Cho et al., 21 Oct 2025) in Section 6.1 (1 S + 2 Nf Q), Conformal window