Measuring cosmological parameters with cosmic microwave background experiments.

The cosmic microwave background anisotropy is sensitive to the slope and amplitude of primordial energy density and gravitational wave fluctuations, the baryon density, the Hubble constant, the cosmological constant, the ionization history, etc. In this Letter, we examine the degree to which these factors can be separately resolved from combined smalland large-angular scale anisotropy observations. We isolate directions of degeneracy in this cosmic parameter space, but note that other cosmic observations can break the degeneracy. PACS NOs: 98.80.Cq, 98.80.Es, 98.70.Vc Typeset using REVTEX The observation of large-angular scale (∼ 10) fluctuations in the Cosmic Microwave Background(CMB) [1,2] marks the beginning of a new age of precision measurement in cosmology [3–10]. Dramatic improvements in largeand small-angular scale (< ∼ 1) experiments [3–10] are anticipated. In this Letter, we explore the degree to which the CMB anisotropy observations can determine cosmological parameters such as the slope of the