Precise measurement of the left-right asymmetry in Z⁰ boson production by e⁺e⁻ collisions : polarization measurement with the quartz fiber calorimeter

This thesis presents a precise measurement of the left-right cross section asymmetry (A_LR) of the Z⁰ boson production by e⁺e^- collision. The measurement is based on the complete data set of 537k Z⁰ events collected by the SLD detector at the SLAC Linear Collider. The pole value of the asymmetry, A⁰_LR was found to be 0.15138 ± 0.00216, which is equivalent to the effective weak mixing angle of sin2Θ^{e ƒ ƒW = 0.23097 ± 0.00027. A technique for a high energy electron beam polarization measurement, based on scattering the beam off a circularly polarized laser light and using a total absorption calorimeter to detect Compton photons, is also presented. The QFC polarimeter based on this technique has been built and successfully operated at the SLAC Linear Collider, resulting in an improvement of the electron beam polarization measurement accuracy, which is critical for a precise A0_LR measurement. Applicability of this technique for use in future e+e- collider experiments is discussed.}