  We propose an inflationary scenario based on a many-flavor hidden QCD with
eight flavors, which realizes the almost scale-invariant (walking) gauge
dynamics. The theory predicts two types of composite (pseudo) Nambu-Goldstone
bosons, the pions and the lightest scalar (dilaton) associated with the
spontaneous chiral symmetry breaking and its simultaneous violation of the
approximate scale invariance. The dilaton acts as an inflaton, where the
inflaton potential is induced by the nonperturbative-scale anomaly linked with
the underlying theory. The inflaton potential parameters are highly constrained
by the walking nature, which are evaluated by straightforward nonperturbative
analyses including lattice simulations. Due to the pseudo Nambu-Goldstone
boson's natures and the intrinsic property for the chiral symmetry breaking in
the walking gauge dynamics, the inflaton coupled to the pions naturally
undergoes the small field inflation consistently with all the cosmological and
astrophysical constraints presently placed by Planck 2018 data. When the theory
is vector-likely coupled to the standard model in part in a way to realize a
dynamical electroweak symmetry breaking, the reheating temperature is
determined by the pion decays to electroweak gauge bosons. The proposed
inflationary scenario would provide a dynamical origin for the small field
inflation as well as the light pions as a smoking-gun to be probed by future
experiments.
