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 \ in the first flight of the MAXIMA balloon-borne experiment (MAXIMA-1) and the low \ results from COBE/DMR. We find constraints on the total energy density of the universe, \=1. 0^+0. 15-₀. ₃₀, the physical density of baryons, \₁h²=0. 03 +/- 0. 01, the physical density of cold dark matter, \₂₃₌h²=0. 2^+0. 2-₀. ₁, and the spectral index of primordial scalar fluctuations, nₛ=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\_\0. 75 and 0. 25\₌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.