Ruling out the power-law form of the scalar primordial spectrum
  Combining Planck CMB temperature [1] and BICEP2 B-mode polarization data
[2,3] we show qualitatively that, assuming inflationary consistency relation,
the power-law form of the scalar primordial spectrum is ruled out at more than
$3\sigma$ CL. This is an important finding, since the power-law form of the
scalar primordial spectrum is one of the main assumptions of concordance model
of cosmology and also a direct prediction of many inflationary scenarios. We
show that a break or step in the form of the primordial scalar perturbation
spectrum, similar to what we studied recently analyzing Planck data [4] can
address both Planck and BICEP2 results simultaneously. Our findings also
indicate that the data may require more flexibilities than what running of
scalar spectral index can provide. Finally we show that an inflaton potential,
originally appeared in [5] can generate both the step and the break model of
scalar primordial spectrum in two different limits. The discussed potential is
found to be favored by Planck data but marginally disfavored by BICEP2 results
as it produces slightly lower amplitude of tensor primordial spectrum. Hence,
if the tensor-to-scalar ratio ($r$) quoted by BICEP2 persists, it is of
importance that we generate inflationary models with large $r$ and at the same
time provide suppression in scalar primordial spectrum at large scales.
