The Annulus‐filteredEandBModes in Cosmic Microwave Background Radiation Polarization

Although it has previously been recognized that the CMB polarizationmeasurement on a sky ring is able to separate the B and E-mode patterns, weshow that the rotational symmetry of the CMB polarization measurement is indeedunique, in that it enables the B and E modes to be separately measured in asimple and clean manner. The separation of B and E modes can in principle beachieved even with a single-polarization detector of arbitrary beam pattern.Based on this premise, a specific observing strategy is suggested, where thetelescope scans along a sky circle with the polarimeter axis always oriented toa fixed direction with respect to the radial direction of the sky circle. Theobservational strategy for B-mode measurements can further be refined bychoosing appropriate beam sizes to suppress the accidental E-mode leakage. Wepresent the expected variances of the measured E and B-mode surface-brightnessfluctuations as functions of the sky annulus radius and beam size. The measuredpeak power is expected to be up to 10% of the total power contained in the CMBpolarization fluctuations for both B and E modes. The temperature-polarization,or T-E, correlation can be measured by the present method as well. By adoptingthis strategy, the AMiBA experiment is expected to detect, in a single skyannulus, a 1\sigma$ B-mode signal in 340 hours.Comment: 46 pages with 14 figures, accepted by ApJ. The substantially expanded revision contains the finite-beam effect for improving the extraction of B mode