Latest inflation model constraints from cosmic microwave background measurements: Addendum

In this addendum to Phys. Rev. D 74, 023502 (2006), we present an update of cosmological constraints on single-field inflation in light of the Wilkinson Microwave Ansiotropy Probe satellite mission five-year results (WMAP5). We find that the cosmic microwave background data are quite consistent with a Harrison-Zel'dovich primordial spectrum with no running and zero tensor amplitude. We find that the three main conclusions of our analysis of the WMAP three-year data (WMAP3) are consistent with the WMAP5 data: (1) the Harrison-Zel'dovich model is within the 95% confidence level contours; (2) there is no evidence for running of the spectral index of scalar perturbations; (3) from the WMAP 5 data alone, potentials of the form V proportional to phi(p) are consistent with the data for p=2 and are ruled out for p=4. Furthermore, consistent with our WMAP3 analysis, we find no evidence for primordial tensor perturbations, this time with a 95% confidence upper limit of r < 0.4 for the WMAP5 data alone, and r < 0.35 for the WMAP5 data taken in combination with the Arcminute Cosmology Bolometer Array (ACBAR).