Constraint on the primordial gravitational waves from the joint analysis of BICEP2 and Planck HFI 353 GHz dust polarization data

Abstract

We make a joint analysis of BICEP2 and recently released Planck HFI 353 GHz dust polarization data, and find that there is no evidence for the primordial gravitational waves and the bound on the tensor-to-scalar ratio becomes r < 0.083 at 95% confidence level in the base ΛCDM + tensor model. Extending to the model with running of scalar spectral index, the bound is a little bit relaxed to r < 0.116 at 95% confidence level. Our results imply that the inflation model with a single monomial potential is marginally disfavored at around 95% confidence level. Especially, the m²ϕ²/2 inflation model is disfavored at more than 2σ level. However, the Starobinsky inflation model gives a nice fit.