Cosmological Parameters from Cosmic Background Imager Observations and Comparisons with BOOMERANG, DASI, and MAXIMA

We report on the cosmological parameters derived from observations with theCosmic Background Imager (CBI), covering 40 square degrees and the multipolerange 300 < l < 3500. The angular scales probed by the CBI correspond tostructures which cover the mass range from 10^14 to 10^17 M_sun, and theobservations reveal, for the first time, the seeds that gave rise to clustersof galaxies. These unique, high-resolution observations also show damping inthe power spectrum to l ~ 2000, which we interpret as due to the finite widthof the photon-baryon decoupling region and the viscosity operating atdecoupling. Because the observations extend to much higher l the CBI resultsprovide information complementary to that probed by the Boomerang, DASI,Maxima, and VSA experiments. As the observations are pushed to highermultipoles no anomalies relative to standard models appear, and extremely goodconsistency is found between the cosmological parameters derived for the CBIobservations over the range 610 < l < 2000 and observations at lower l[abridged].Comment: Accepted by the Astrophysical Journal; 22 pages including 14 color figures. v2: new analysis with better sampling in parameter space and including VSA dat