Coleman-Weinberg Inflation in light of Planck
  We revisit a single field inflationary model based on Coleman-Weinberg
potentials. We show that in small field Coleman-Weinberg inflation, the
observed amplitude of perturbations needs an extremely small quartic coupling
of the inflaton, which might be a signature of radiative origin. However, the
spectral index obtained in a standard cosmological scenario turns out to be
outside the 2 sigma region of the Planck data. When a non-standard cosmological
framework is invoked, such as brane-world cosmology in the Randall-Sundrum
model, the spectral index can be made consistent with Planck data within 1
sigma, courtesy of the modification in the evolution of the Hubble parameter in
such a scheme. We also show that the required inflaton quartic coupling as well
as a phenomenologically viable B-L symmetry breaking together with a natural
electroweak symmetry breaking can arise dynamically in a generalized B-L
extension of the Standard Model where the full potential is assumed to vanish
at a high scale.
