Slow onset type PCA events and associated pre-SSC polar geomagnetic disturbances

Observation of polar geomagnetic disturbances in connection with polar cap absorptions of slow onset typ

A possible nuclear effect on the NuTeV sin^2 theta_W anomaly

We investigate a possible explanation for the NuTeV anomaly in terms of a nuclear correction difference between u_v and d_v distributions. Analyzing deep elastic scattering and Drell-Yan data for nuclear targets, we try to determine the correction difference and its effect on the anomaly. We find that the difference cannot be precisely determined at this stage due to the lack of data which are sensitive to the difference. Therefore, it is difficult to draw a solid conclusion about its effect although the anomaly could be explained, at least partially, by this kind of nuclear correction.Comment: 3 pages, 1 figure, to be published in the proceedings of the XVIIth Particles and Nuclei International Conference (PANIC), Santa Fe, New Mexico, USA, October 24-28, 200

Calibration System with Cryogenically-Cooled Loads for CMB Polarization Detectors

We present a novel system to calibrate millimeter-wave polarimeters for CMB polarization measurements. This technique is an extension of the conventional metal mirror rotation approach, however it employs cryogenically-cooled blackbody absorbers. The primary advantage of this system is that it can generate a slightly polarized signal ($\sim100$ mK) in the laboratory; this is at a similar level to that measured by ground-based CMB polarization experiments observing a $\sim$ 10 K sky. It is important to reproduce the observing condition in the laboratry for reliable characterization of polarimeters before deployment. In this paper, we present the design and principle of the system, and demonstrate its use with a coherent-type polarimeter used for an actual CMB polarization experiment. This technique can also be applied to incoherent-type polarimeters and it is very promising for the next-generation CMB polarization experiments.Comment: 7 pages, 9 figures Submitted to RS

Innovative Demodulation Scheme for Coherent Detectors in CMB Experiments

We propose an innovative demodulation scheme for coherent detectors used in cosmic microwave background polarization experiments. Removal of non-white noise, e.g., narrow-band noise, in detectors is one of the key requirements for the experiments. A combination of modulation and demodulation is used to extract polarization signals as well as to suppress such noise. Traditional demodulation, which is based on the two- point numerical differentiation, works as a first-order high pass filter for the noise. The proposed demodulation is based on the three-point numerical differentiation. It works as a second-order high pass filter. By using a real detector, we confirmed significant improvements of suppression power for the narrow-band noise. We also found improvement of the noise floor.Comment: 3 pages, 4 figure