DBI Galileon inflation in the light of Planck 2015
  In this work we consider a DBI Galileon (DBIG) inflationary model and
constrain its parameter space with the Planck 2015 and BICEP2/Keck array and
Planck (BKP) joint analysis data by means of a potential independent analysis.
We focus our attention on inflationary solutions characterized by a constant or
varying sound speed as well as warp factor. We impose bounds on stringy aspects
of the model, such as the warp factor $\left(f\right)$ and the induced gravity
parameter $\left(\tilde{m}\right)$. We study the parameter space of the model
and find that the tensor-to-scalar ratio can be as low as
$r\simeq6\times10^{-4}$ and inflation happens to be at GUT scale. In addition,
we obtain the tilt of the tensor power spectrum and test the standard
inflationary consistency relation $\left(r=-8n_{t}\right)$ against the latest
bounds from the combined results of BKP+Laser Interferometer
Gravitational-Waves Observatory (LIGO), and find that DBIG inflation predicts a
red spectral index for the tensor power spectrum.
