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

$\xi $(all hadronic modes) PARAMETER

INSPIRE   PDGID:
S035XAL
($\mathit V−\mathit A$) theory predicts $\xi $ = $1$.
VALUE EVTS DOCUMENT ID TECN  COMMENT
$\bf{ 0.995 \pm0.007}$ OUR FIT
$\bf{ 0.997 \pm0.007}$ OUR AVERAGE
$0.992$ $\pm0.007$ $\pm0.008$ 102k 1
HEISTER
2001E
 ALEP 1991--1995 LEP runs
$0.997$ $\pm0.027$ $\pm0.011$ 39k 2
ABREU
2000L
 DLPH 1992--1995 runs
$1.02$ $\pm0.13$ $\pm0.03$ 17.2k 3
ASNER
2000
CLEO ${\it{}E}^{\it{}ee}_{\rm{}cm}$= $10.6$ GeV
$1.032$ $\pm0.031$ 37k 4
ACCIARRI
1998R
 L3 $1991 - 1995$ LEP runs
$0.93$ $\pm0.10$ $\pm0.04$
ABE
1997O
 SLD 1993--1995 SLC runs
$1.29$ $\pm0.26$ $\pm0.11$ 7.4k 5
ACKERSTAFF
1997R
 OPAL 1992--1994 LEP runs
$0.995$ $\pm0.010$ $\pm0.003$ 66k 6
ALEXANDER
1997F
 CLEO ${\it{}E}^{\it{}ee}_{\rm{}cm}$= $10.6$ GeV
$1.03$ $\pm0.06$ $\pm0.04$ 2.0k 7
COAN
1997
CLEO ${\it{}E}^{\it{}ee}_{\rm{}cm}$= $10.6$ GeV
$1.017$ $\pm0.039$ 8
ALBRECHT
1995C
 ARG ${\it{}E}^{\it{}ee}_{\rm{}cm}$= $9.5 - 10.6$ GeV
$1.25$ $\pm0.23$ ${}^{+0.15}_{-0.08}$ 7.5k 9
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. • •
$0.970$ $\pm0.053$ $\pm0.011$ 14k 10
ACCIARRI
1996H
 L3 Repl. by ACCIARRI 1998R
$1.08$ ${}^{+0.46}_{-0.41}$ ${}^{+0.14}_{-0.25}$ 2.6k 11
AKERS
1995P
 OPAL Repl. by ACKERSTAFF 1997R
$1.006$ $\pm0.032$ $\pm0.019$ 12
BUSKULIC
1995D
 ALEP Repl. by HEISTER 2001E
$1.022$ $\pm0.028$ $\pm0.030$ 1.7k 13
ALBRECHT
1994E
 ARG ${\it{}E}^{\it{}ee}_{\rm{}cm}$= $9.4 - 10.6$ GeV
$0.99$ $\pm0.07$ $\pm0.04$ 14
BUSKULIC
1994D
 ALEP 1990+1991 LEP run
$1.14$ $\pm0.34$ ${}^{+0.34}_{-0.17}$ $3.9$k 9
ALBRECHT
1990I
 ARG Repl. by ALBRECHT 1993C
1  HEISTER 2001E quote $0.992$ $\pm0.007$ $\pm0.006\pm0.005$ where the errors are statistical, systematic, and an uncertainty due to the final state model. We combine the systematic error and model uncertainty. They use ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit \nu}_{{{\tau}}}}$, ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit K}}{{\mathit \nu}_{{{\tau}}}}$, ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \rho}}{{\mathit \nu}_{{{\tau}}}}$, and ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit a}_{{{1}}}}{{\mathit \nu}_{{{\tau}}}}$ decays.
2  ABREU 2000L use ${{\mathit \tau}^{-}}$ $\rightarrow$ ${{\mathit h}^{-}}{}\geq{}$ 0 ${{\mathit \pi}^{0}}{{\mathit \nu}_{{{\tau}}}}$ decays.
3  ASNER 2000 use ${{\mathit \tau}^{-}}$ $\rightarrow$ ${{\mathit \pi}^{-}}$2 ${{\mathit \pi}^{0}}{{\mathit \nu}_{{{\tau}}}}$ decays.
4  ACCIARRI 1998R use ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit \nu}_{{{\tau}}}}$, ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit K}}{{\mathit \nu}_{{{\tau}}}}$, and ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \rho}}{{\mathit \nu}_{{{\tau}}}}$ decays.
5  ACKERSTAFF 1997R use ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit a}_{{{1}}}}{{\mathit \nu}_{{{\tau}}}}$ decays.
6  ALEXANDER 1997F use ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \rho}}{{\mathit \nu}_{{{\tau}}}}$ decays.
7  COAN 1997 use ${{\mathit h}^{+}}{{\mathit h}^{-}}$ energy correlations.
8  Combined fit to ARGUS tau decay parameter measurements in ALBRECHT 1995C, ALBRECHT 1993G, and ALBRECHT 1994E.
9  Uses ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit a}_{{{1}}}}{{\mathit \nu}_{{{\tau}}}}$ decays. Replaced by ALBRECHT 1995C.
10  ACCIARRI 1996H use ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit \nu}_{{{\tau}}}}$, ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit K}}{{\mathit \nu}_{{{\tau}}}}$, and ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \rho}}{{\mathit \nu}_{{{\tau}}}}$ decays.
11  AKERS 1995P use ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit a}_{{{1}}}}{{\mathit \nu}_{{{\tau}}}}$ decays.
12  BUSKULIC 1995D use ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit \nu}_{{{\tau}}}}$, ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \rho}}{{\mathit \nu}_{{{\tau}}}}$, and ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit a}_{{{1}}}}{{\mathit \nu}_{{{\tau}}}}$ decays.
13  ALBRECHT 1994E measure the square of this quantity and use the sign determined by ALBRECHT 1990I to obtain the quoted result. Uses ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit a}_{{{1}}}}{{\mathit \nu}_{{{\tau}}}}$ decays. Replaced by ALBRECHT 1995C.
14  BUSKULIC 1994D use ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit \nu}_{{{\tau}}}}$ and ${{\mathit \tau}}$ $\rightarrow$ ${{\mathit \rho}}{{\mathit \nu}_{{{\tau}}}}$ decays. Superseded by BUSKULIC 1995D.
References