Constraint on inflation model from BICEP2 and WMAP 9-year data

Even though Planck data released in 2013 (P13) is not compatible with Background Imaging of Cosmic Extragalactic Polarization (B2) and some local cosmological observations, including Supernova Legacy Survey (SNLS) samples and H-0 prior from Hubble Space Telescope (HST) etc. Wilkinson Microwave Anisotropy Probe 9-year data (W9) is consistent with all of them in the base six-parameter Lambda CDM+ tensor cosmology quite well. In this paper, we adopt the combinations of B2+W9 and B2+W9+SNLS+BAO+HST to constrain the cosmological parameters in the base sixparameter Lambda CDM+ tensor model with n(t) = -r/8, where r and nt are the tensor-to-scalar ratio and the tilt of relic gravitational wave spectrum, and BAO denotes Baryon Acoustic Oscillation (BAO). We find that the Harrison-Zel'dovich (HZ) scale invariant scalar power spectrum is consistent with both data combinations, chaotic inflation is marginally disfavored by the data at around 2 sigma level, but the power-law inflation model and the inflation model with inverse power-law potential can fit the data nicely.