tau - Particle Data Group

Citation: K. Nakamura et al. (Particle Data Group), JP G 37, 075021 (2010) and 2011 partial update for the 2012 edition (URL: http://pdg.lbl.gov)
WEIGHTED AVERAGE
0.290±0.018 (Error scaled by 2.4)
Values above of weighted average, error,
and scale factor are based upon the data in
this ideogram only. They are not necessarily
the same as our ‘best’ values,
obtained from a least-squares constrained fit
utilizing measurements of other (related)
quantities as additional information.
0.1 0.2 0.3 0.4 0.5 0.6
(
Γ K − π + π − ν τ (ex.K 0 )
) /Γ total (%)
LEE 10 BELL
χ 2
5.4
AUBERT 08 BABR 3.5
ABBIENDI 04J OPAL
BRIERE 03 CLE3 5.4
RICHICHI 99 CLEO
BARATE 98 ALEP 2.6
16.9
(Confidence Level = 0.0007)
Γ ( K − π + π − ν τ (ex.K 0 ) ) /Γ ( π − π + π − ν τ (ex.K 0 ) ) Γ 85 /Γ 60
VALUE (units 10 −2 ) EVTS DOCUMENT ID TECN COMMENT
3.92±0.02 +0.15
−0.16
794k 1 LEE 10 BELL 666 fb −1 E ee
cm = 10.6 GeV
1 Not independent of LEE 10 Γ(τ − → K − π + π − ντ (ex.K 0 ))/Γ total and Γ(τ − →
π − π + π − ν τ (ex.K 0 ))/Γ total values.
Γ ( K − ρ 0 ν τ → K − π + π − ) (
ν τ /Γ K − π + π − ν τ (ex.K 0 ) ) Γ 86 /Γ 85
VALUE DOCUMENT ID TECN COMMENT
0.48±0.14±0.10 1 ASNER 00B CLEO E ee
cm =10.6 GeV
•••We do not use the following data for averages, fits, limits, etc. •••
0.39±0.14 2 BARATE 99R ALEP 1991–1995 LEP runs
1 ASNER 00B assume τ − → K − π + π − ντ (ex. K 0 ) decays proceed only through K ρ and
K ∗ π intermediate states. They assume the resonance structure of τ − → K − π + π − ν τ
(ex. K 0 ) decays is dominated by K 1 (1270) − and K 1 (1400) − resonances, and assume
B(K 1 (1270) → K ∗ (892)π) =(16± 5)%, B(K 1 (1270) → K ρ) =(42± 6)%, and
B(K 1 (1400) → K ρ) =0.
2 BARATE 99R assume τ − → K − π + π − ντ (ex. K 0 ) decays proceed only through K ρ
and K ∗ π intermediate states. The quoted error is statistical only.
Γ ( K − π + π − π 0 ) ν τ /Γtotal
VALUE (units 10 −4 )
13.5±1.4 OURFIT
Γ 87 /Γ = (0.3431Γ 42 +Γ 89 +0.226Γ 128 )/Γ
DOCUMENT ID
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