Constraints on brane inflation after Planck 2015: Impacts of the latest
  local measurement of the Hubble constant
  We investigate the observational constraints on three typical brane inflation
models by considering the latest local measurement of the Hubble constant in
the global fit. We also employ other observational data, including the Planck
2015 CMB data, the BICEP2/Keck Array B-mode data, and the baryon acoustic
oscillations data, in our analysis. Previous studies have shown that the
addition of the latest local $H_{0}$ measurement favors a larger spectral
index, and can exert a significant influence on the model selection of
inflation. In this work, we investigate its impacts on the status of brane
inflation models. We find that, when the direct $H_{0}$ measurement is
considered, the prototype model of brane inflation is still in good agreement
with the current observational data within the $2\sigma$ level range. For the
KKLMMT model, the consideration of the $H_{0}$ measurement allows the range of
the parameter $\beta$ to be amplified to ${\cal O}(10^{-2})$, which slightly
alleviates the fine-tuning problem. For the IR DBI model, the addition of the
$H_{0}$ measurement does not provide a better fit. These results show that the
consideration of the new $H_{0}$ prior can exert a considerable influence on
the brane inflation models. At last, we show that, when $\beta \lesssim 1.1$,
the equilateral non-Gaussianity in the IR DBI inflation model is compatible
with the current CMB data at the 1$\sigma$ level.
