${{\mathit \tau}}$-DECAY PARAMETERS

$\xi ({{\mathit a}_{{{1}}}}$) PARAMETER

INSPIRE   JSON  (beta) PDGID:
S035XA1
($\mathit V−\mathit A$) theory predicts $\xi ({{\mathit a}_{{{1}}}}$) = $1$.
VALUE EVTS DOCUMENT ID TECN  COMMENT
$\bf{ 1.001 \pm0.027}$ OUR FIT
$\bf{ 1.002 \pm0.028}$ OUR AVERAGE
$1.000$ $\pm0.016$ $\pm0.024$ 35k 1
HEISTER
2001E
 ALEP 1991--1995 LEP runs
$1.02$ $\pm0.13$ $\pm0.03$ 17.2k
ASNER
2000
CLEO ${\it{}E}^{\it{}ee}_{\rm{}cm}$= $10.6$ GeV
$1.29$ $\pm0.26$ $\pm0.11$ 7.4k 2
ACKERSTAFF
1997R
 OPAL 1992--1994 LEP runs
$0.85$ ${}^{+0.15}_{-0.17}$ $\pm0.05$
ALBRECHT
1995C
 ARG ${\it{}E}^{\it{}ee}_{\rm{}cm}$= $9.5 - 10.6$ GeV
$1.25$ $\pm0.23$ ${}^{+0.15}_{-0.08}$ 7.5k
ALBRECHT
1993C
 ARG ${\it{}E}^{\it{}ee}_{\rm{}cm}$= $9.4 - 10.6$ GeV
• • We do not use the following data for averages, fits, limits, etc. • •
$1.08$ ${}^{+0.46}_{-0.41}$ ${}^{+0.14}_{-0.25}$ 2.6k 3
AKERS
1995P
 OPAL Repl. by ACKERSTAFF 1997R
$0.937$ $\pm0.116$ $\pm0.064$
BUSKULIC
1995D
 ALEP Repl. by HEISTER 2001E
1  HEISTER 2001E quote $1.000$ $\pm0.016$ $\pm0.013\pm0.020$ where the errors are statistical, systematic, and an uncertainty due to the final state model. We combine the systematic error and model uncertainty.
2  ACKERSTAFF 1997R obtain this result with a model independent fit to the hadronic structure functions. Fitting with the model of Kuhn and Santamaria (ZPHY $\mathbf {C48}$, 445 (1990)) gives $0.87$ $\pm0.16$ $\pm0.04$, and with the model of of Isgur $\mathit et~al$. (PR $\mathbf {D39}$,1357 (1989)) they obtain $1.20$ $\pm0.21$ $\pm0.14$.
3  AKERS 1995P obtain this result with a model independent fit to the hadronic structure functions. Fitting with the model of Kuhn and Santamaria (ZPHY $\mathbf {C48}$, 445 (1990)) gives $0.87$ $\pm0.27$ ${}^{+0.05}_{-0.06}$, and with the model of of Isgur $\mathit et~al$. (PR $\mathbf {D39}$,1357 (1989)) they obtain $1.10$ $\pm0.31$ ${}^{+0.13}_{-0.14}$.
References