  The dilaton low-energy effective field theory (EFT) of an emergent light
scalar is probed in the paradigm of strongly coupled near-conformal gauge
theories. These studies are motivated by models which exhibit small
$\beta$-functions near the conformal window (CW), perhaps with slow
scale-dependent walking and a light scalar with ${ 0^{++} }$ quantum numbers.
We report our results from the hypothesis of a dilaton inspired EFT analysis
with two massless fermions in the two-index symmetric (sextet) representation
of the SU(3) color gauge group. With important caveats in our conclusions,
conformal symmetry breaking entangled with chiral symmetry breaking would drive
the near-conformal infrared behavior of the theory predicting characteristic
dilaton signatures of the light scalar from broken scale invariance when probed
on relevant scales of fermion mass deformations. From a recently reasoned
choice of the dilaton potential in the EFT description~\cite{Golterman:2016lsd}
we find an unexpectedly light dilaton mass in the chiral limit at $m_d/f_\pi =
1.56(28)$, set in units of the pion decay constant $f_\pi$. Subject to further
statistical and systematic tests of continued post-conference analysis, this
result is significantly lower than our earlier estimates from less controlled
extrapolations of the light scalar (the $\sigma$-particle) to the massless
fermion limit of chiral perturbation theory. We also discuss important
distinctions between the dilaton EFT analysis and the linear $\sigma$-model
without dilaton signatures. For comparative reasons, we comment on dilaton
tests from recent work with fermions in the fundamental representation with
$n_f=8$ flavors.
