| Popis: |
Beam normal single spin asymmetry is a special case of asymmetric scattering caused by a two photon exchange process. It was measured to a high precision using the Qweak experimental setup at Jefferson Lab and found to be -5.350 ± 0.067 stat ± 0.137 sys ppm [1]. Following completion of those results, it was discovered that a phi dependent bias asymmetry was generated in the detectors due to an unfortunate combination of rescattering in the lead pre-radiators and geometric factors. The goal of this project was to characterize how the polarization of the electrons at the target moves through the detector system and causes this false asymmetry, and to provide an estimate of the correction to be applied to the results originally presented in ref [1]. While a final correction value has not been reached, the methods have been designed, built, and tested. |
