Upper Limits on Electric and Weak Dipole Moments of Tau-Lepton and Heavy Quarks from e+e- Annihilation

TL;DR

This paper uses LEP e+e- annihilation data to set upper limits on the electric and weak dipole moments of tau leptons and heavy quarks, improving some previous bounds especially for b-quarks.

Contribution

It provides new upper limits on the dipole moments of tau, charm, and bottom quarks derived from experimental cross-section measurements.

Findings

Upper limits on tau electric and weak dipole moments are 3*10^{-17} and 4*10^{-17} e*cm respectively.

Limits for charm quark are 5*10^{-17} (electric) and 7*10^{-17} e*cm (weak).

Significant improvement over previous bounds for b-quark dipole moments.

Abstract

The total cross-sections measured at LEP for e+e- annihilation into tau+tau-, c\bar{c} and b\bar{b} at 2E ~ 200 GeV are used to derive the upper limits 3*10^{-17}, 5*10^{-17}, 2*10^{-17} e*cm for the electric dipole moments and 4*10^{-17}, 7*10^{-17}, 2.5*10^{-17} e*cm for the weak dipole moments of the tau-lepton, c-, and b-quarks, respectively. Some of the existing limits on these moments are improved and for the b-quark the improvement is rather significant.