Measurement of the weak mixing angle at a Super Charm-Tau factory with data-driven monitoring of the average electron beam polarization

Abstract

A method for measuring the average longitudinal polarization of the electron beam at an electron-positron collider operating near the $J/\ddot{I}ˆ$ resonance is proposed. The method utilizes the differential cross-section of $J/\ddot{I}ˆ\to [\hat{I}›\to p\ddot{I}{€}^{-}][\bar{\hat{I}}›\to \bar{p}\ddot{I}{€}^{+}]$ decay. It can be used to measure the average longitudinal polarization of electrons with the statistical precision better than $10^{-3}$ at a Super Charm-Tau factory operating at the luminosity of $10^{35}\mathrm{cm}{}^{-2}\mathrm{s}{}^{-1}$. The method is discussed in the context of the weak mixing angle measurement in the same experiment.

30 pages, 9 figures. Some typos found in the published version are corrected here