More Exact Results on Chiral Gauge Theories: the Case of the Symmetric Tensor

We study dynanics of $SU(N-4)$ gauge theories with fermions in rank-2 symmetric tensor and $N$ anti-fundamental representations, by perturbing supersymmetric theories with anomaly-mediated supersymmetry breaking. We find the $SU(N)times U(1)$ global symmetry is dynamically broken to $SO(N)$ for $Ngeq 17$, a different result from conjectures in the literature. For $N<17$, theories flow to infrared fixed points.