Dark Radiation and Inflationary Freedom
  We perform a cosmological analysis in which we allow the primordial power
spectrum of scalar perturbations to assume a shape that is different with
respect to the usual power-law, arising from the simplest models of
cosmological inflation. We parametrize the primordial power spectrum with a
piecewise monotone cubic Hermite function and we use it to investigate how the
constraints on the various cosmological parameters change: we find that the
obtained limits are relaxed with respect to the power-law case, if CMB
polarization data are not included. Moreover, the cosmological analyses provide
us some indications about the shape of the reconstructed primordial power
spectrum, where we notice possible features around
$k\simeq0.002\,\mathrm{Mpc}^{-1}$ and $k\simeq0.0035\,\mathrm{Mpc}^{-1}$. If
confirmed in future analyses involving enhanced experimental data, these
features suggests that the simplest cosmological inflation models may be
incomplete.
