Speaker
Description
A polarized electron beam is being considered as an upgrade for the SuperKEKB accelerator, which would enable a new precision electroweak physics program at Belle II. Many of these electroweak tests are preformed with experimental measurements of the left-right asymmetry, $A_{LR}$, where the expected level of precision at Belle II dictates at least one loop calculations from theory. We have tested the level of agreement in NLO calculations of $A_{LR}$ for Bhabhas, against a Monte Carlo generation of the asymmetry with the new ReneSANCe generator. For future experimental measurements of $A_{LR}$ the expected limiting uncertainty is the average beam polarization. A new technique, Tau Polarimetry, has been shown to be capable of measuring the average beam polarization to better than half a percent. This has been implemented at the $B\kern-0.1em{\small A}\kern-0.1em B\kern-0.1em{\small A\kern-0.2em R}$ experiment, a precursor experiment to Belle II, and the average beam polarization of it's associated accelerator, PEP-II, precisely measured. This presentation will present the technique, including its systematic uncertainties, using the full $B\kern-0.1em{\small A}\kern-0.1em B\kern-0.1em{\small A\kern-0.2em R}$ $\Upsilon$(4S) dataset.
