New measurements of fine-scale CMB polarization power spectra from CAPMAP at both 40 and 90 GHz

We present new measurements of the CMB polarization from the final season of CAPMAP. The data set was obtained in winter 2004-2005 with the 7 m antenna in Crawford Hill, New Jersey, from 12 W-band (84-100 GHz) and four Q-band (36-45 GHz) correlation Polarimeters with 3.3′ and 6.5′ beam sizes, respectively. After selection criteria were applied, 956 (939) hr of data survived for analysis of W-band (Q-band) data. Two independent and complementary pipelines produced results in excellent agreement with each other. A broad suite of null tests, as well as extensive simulations, showed that systematic errors were minimal, and a comparison of the W-band and Q-band sky maps revealed no contamination from galactic foregrounds. We report the E-mode and B-mode power spectra in seven bands in the range 200 ≤ℓ ≤3000, extending the range of previous measurements to higher ℓ The E-mode spectrum, which is detected at 11 σ significance, is in agreement with cosmological predictions and with previous work at other frequencies and angular resolutions. The BB power spectrum provides one of the best limits to date on B-mode power at 4.8 μK² (95% confidence).