${{\mathit \tau}}$ ELECTRIC DIPOLE MOMENT ($\mathit d_{{{\mathit \tau}}}$)

A nonzero value is forbidden by both $\mathit T$ invariance and $\mathit P$ invariance.
The $\mathit q{}^{2}$ dependence is expected to be small providing no thresholds are nearby.

Im($\mathit d_{{{\mathit \tau}}}$)

INSPIRE   JSON  (beta) PDGID:
S035EDI
VALUE ($ 10^{-16} $ $\mathit e~$cm) CL% DOCUMENT ID TECN  COMMENT
$\bf{-0.103\text{ to }0.023 }$ 95 1
INAMI
2022
BELL ${\it{}E}^{\it{}ee}_{\rm{}cm}$ = 10.6 GeV
• • We do not use the following data for averages, fits, limits, etc. • •
$-0.25\text{ to }0.008 $ 95 2
INAMI
2003
BELL ${\it{}E}^{\it{}ee}_{\rm{}cm}$= 10.6 GeV
$<1.8$ 95 3
ALBRECHT
2000
ARG ${\it{}E}^{\it{}ee}_{\rm{}cm}$= $10.4$ GeV
1  INAMI 2022 use ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$ events from 833 fb${}^{-1}$ of data. Also report a measurement of Im(d$_{\tau }$) = ($-0.40$ $\pm0.32$) $ \times 10^{-17}{{\mathit e}}$cm.
2  INAMI 2003 use ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$ events.
3  ALBRECHT 2000 use ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \tau}^{+}}{{\mathit \tau}^{-}}$ events. Limit is on the absolute value of Im($\mathit d_{{{\mathit \tau}}}$).
References