  We report the final results of our study of the cosmic microwave background
(CMB) with the BIMA array. Over 1000 hours of observation were dedicated to
this project exploring CMB anisotropy on scales between 1' and 2' in eighteen
6.6' FWHM fields. In the analysis of the CMB power spectrum, the visibility
data is divided into two bins corresponding to different angular scales.
Modeling the observed excess power as a flat band of average multipole ell=
5237, we find Delta T_1^2=220_{-120}^{+140} muK^2 at 68% confidence and Delta
T_1^2 >0 muK^2 with 94.7% confidence. In a second band with average multipole
of ell = 8748, we find Delta T_2^2 consistent with zero, and an upper limit 880
muK^2 at 95% confidence. An extensive series of tests and supplemental
observations with the VLA provide strong evidence against systematic errors or
radio point sources being the source of the observed excess power. The dominant
source of anisotropy on these scales is expected to arise from the
Sunyaev-Zel'dovich (SZ) effect in a population of distant galaxy clusters. If
the excess power is due to the SZ effect, we can place constraints on the
normalization of the matter power spectrum sigma_8 = 1.03^{+0.20}_{-0.29} at
68% confidence. The distribution of pixel fluxes in the BIMA images are found
to be consistent with simulated observations of the expected SZ background and
rule out instrumental noise or radio sources as the source of the observed
excess power with similar confidence to the detection of excess power.
Follow-up optical observations to search for galaxy over-densities
anti-correlated with flux in the BIMA images, as might be expected from the SZ
effect, proved to be inconclusive.
