First Measurements of the Polarization of the Cosmic Microwave Background Radiation at Small Angular Scales from CAPMAP

Polarization results from the Cosmic Anisotropy Polarization MAPper (CAPMAP)experiment are reported. These are based upon 433 hours, after cuts, observinga 2 square degree patch around the North Celestial Pole (NCP) with four 90 GHzcorrelation polarimeters coupled to optics defining $4\arcmin$ beams. TheE-mode flat bandpower anisotropy within $\ell=940^{+330}_{-300}$ is measured as66$^{+69}_{-29} \mu$K$^2$; the 95% Confidence level upper limit for B-modepower within $\ell=1050^{+590}_{-520}$ is measured as 38 $\mu$K$^2$.Comment: 4 pages, 2 figures; corrected formatting and comments of second version, identical in substance. In the first version the wrong concordance model was used, results (fit to multiplier to concordance model) and figures have been updated to the proper one. In the first version the central 68% regions were quoted, while now the 68% confidence intervals of highest posterior density are give