COSMOLOGICAL PARAMETERS FROM THE QUAD CMB POLARIZATION EXPERIMENT

Abstract

In this paper, we present a parameter estimation analysis of the polarization and temperature power spectra from the
\nsecond and third season of observations with the QUaD experiment. QUaD has for the first time detected multiple
\nacoustic peaks in the E-mode polarization spectrum with high significance. Although QUaD-only parameter
\nconstraints are not competitive with previous results for the standard six-parameter ΛCDM cosmology, they do
\nallow meaningful polarization-only parameter analyses for the first time. In a standard six-parameter ΛCDM
\nanalysis, we find the QUaD TT power spectrum to be in good agreement with previous results. However, the QUaD
\npolarization data show some tension with ΛCDM. The origin of this 1σ–2σ tension remains unclear, and may point
\nto new physics, residual systematics, or simple random chance. We also combine QUaD with the five-year WMAP
\ndata set and the SDSS luminous red galaxies 4th data release power spectrum, and extend our analysis to constrain
\nindividual isocurvature mode fractions, constraining cold dark matter density, αcdmi < 0.11 (95% confidence limit
\n(CL)), neutrino density, αndi < 0.26 (95% CL), and neutrino velocity, αnvi < 0.23 (95% CL), modes. Our analysis
\nsets a benchmark for future polarization experiments.