Suggestion for measuring the weak dipole moment of $\tau$ lepton at Z-factory

TL;DR

This paper proposes three new observables for Z-factory experiments to measure the weak dipole moment of the tau lepton, which could significantly enhance detection sensitivity compared to previous methods at LEP-I.

Contribution

The paper introduces three novel observables with larger linear coefficients for measuring the tau's weak dipole moment, improving potential detection sensitivity.

Findings

New observables depend linearly on the real and imaginary parts of $d_w^\tau$

The slopes of the new observables are much larger than those used at LEP-I

Recommends using these observables for future or re-analyzed LEP-I data

Abstract

Three new observables for Z-factory to measure the weak dipole moment of $\tau$ lepton ($d_w^\tau$) are proposed. As those observables employed at LEP-I, the new observables depend on the real and imaginary parts of $d_w^\tau$ linearly, thus we calculate the slopes, i.e. the linear coefficients of the dependence, precisely and find that the obtained slopes are much lager than those employed at LEP-I. It means that the signal for the weak dipole moment $d_w^\tau$ may be enhanced quite a lot, if one employs the new observables. Being superior to those at LEP-I, we recommend measuring the weak dipole moment $d_w^\tau$ in terms of the new observables if re-analyzing the data of LEP-I or doing the measurement at a possible Z-factory in the near future.