Constraints on Cosmological Parameters from MAXIMA-1

We set new constraints on a seven-dimensional space of cosmological parameters within the class of inflationary adiabatic models. We use the angular power spectrum of the cosmic microwave background measured over a wide range of l in the first flight of the MAXIMA balloon-borne experiment (MAXIMA-1) and the low-l results from the COBE Differential Microwave Radiometer experiment. We find constraints on the total energy density of the universe, Ω=1.0^+0.15_-0.30, the physical density of baryons, Ω_bh²=0.03+/-0.01, the physical density of cold dark matter, Ω_cdmh²=0.2^+0.2_-0.1, and the spectral index of primordial scalar fluctuations, n_s=1.08+/-0.1, all at the 95% confidence level. By combining our results with measurements of high-redshift supernovae we constrain the value of the cosmological constant and the fractional amount of pressureless matter in the universe to 0.45<Ω_Λ<0.75 and 0.25<Ω_m<0.50, at the 95% confidence level. Our results are consistent with a flat universe and the shape parameter deduced from large-scale structure, and in marginal agreement with the baryon density from big bang nucleosynthesis.