HFAG-Tau Summer 2011 Web Report


Content

  • Tau Mass
  • Leptonic Branching Fractions
  • Strange Branching Fractions
  • Non-Strange Branching Fractions
  • Un-Constrained Global Fit
  • Unitarity Constrained Global Fit
  • Lepton Universality
  • Extraction of |Vus|
  • Results from Global Fit to Non-B-Factory Data
  • Results from Global Fit including B-Factory Data
  • Lepton Flavour Violating Upper Limits
  • Search for CP Violaion
  • Mass Spectrun Data
  • Plot gallery

  • Tau Mass:

    Decay Mode Experiment Reference Results Averages
    τ- → π- π- π+ ν BaBar Phys.Rev.D80:092005,2009 (1776.68 ± 0.12 ± 0.41) MeV
    TauMass.eps

    TauMass.gif

    Belle Phys.Rev.Lett.99:011801,2007 (1776.61 ± 0.13 ± 0.35) MeV
    KEDR Tau08 (1776.69 +0.17-0.19 ± 0.15) MeV
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    Leptonic Branching Fractions:

    Decay Mode Experiment Reference Results Averages
    - → µ- ν ν)/ (τ- → e- ν ν) BaBar Phys.Rev.Lett.105:051602,2010 (0.9796 ± 0.0016 ± 0.0036)
    - → µ- ν ν).eps

    - → µ- ν ν).gif

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    Strange Branching Fractions:

    Decay Mode Experiment Reference Results Averages
    - → K- ν)/(τ- → e- ν ν) BaBar Phys.Rev.Lett.105:051602,2010 (0.03882 ± 0.00032 ± 0.00057)
    - → K- ν).eps

    - → K- ν).gif

    τ- → K- π0 ν BaBar Phys.Rev.D76:051104,2007 (0.416 ± 0.003 ± 0.018) x 10-2
    - → K- π0 ν).eps

    - → K- π0 ν).gif

    τ-K0 π- ν BaBar arXiv:0808.1121 [hep-ex] (0.840 ± 0.004 ± 0.023) x 10-2
    -K0 π- ν).eps

    -K0 π- ν).gif

    Belle Phys.Lett.B654:65-73,2007 (0.808 ± 0.004 ± 0.026) x 10-2
    τ-K0 π- π0ν BaBar arXiv:0910.2884 [hep-ex] (0.342 ± 0.006 ± 0.015) x 10-2
    -K0 π- π0ν).eps

    -K0 π- π0ν).gif

    τ- → K- π- π+ ν (ex. KS0) BaBar Phys.Rev.Lett.100:011801,2008 (0.273 ± 0.002 ± 0.009) x 10-2
    - → K- π- π+ ν (ex. KS0)).eps

    - → K- π- π+ ν (ex. KS0)).gif

    Belle Phys.Rev.D81:113007,2010 (0.330 ± 0.001 +0.016-0.017) x 10-2
    τ- → K- π- K+ ν BaBar Phys.Rev.Lett.100:011801,2008 (1.346 ± 0.010 ± 0.036) x 10-3
    - → K- π- K+ ν).eps

    - → K- π- K+ ν).gif

    Belle Phys.Rev.D81:113007,2010 (1.55 ± 0.01 +0.06-0.05) x 10-3
    τ- → K- K- K+ ν BaBar Phys.Rev.Lett.100:011801,2008 (1.58 ± 0.13 ± 0.12) x 10-5
    - → K- K- K+ ν).eps

    - → K- K- K+ ν).gif

    Belle Phys.Rev.D81:113007,2010 (3.29 ± 0.17 +0.19-0.20) x 10-5
    τ- → K- φ ν BaBar Phys.Rev.Lett.100:011801,2008 (3.39 ± 0.20 ± 0.28) x 10-5
    - → K- φ ν).eps

    - → K- φ ν).gif

    Belle Phys.Lett.B643:5-10,2006 (4.05 ± 0.25 ± 0.26) x 10-5
    τ- → K- K* ν Belle arXiv:0808.1059 [hep-ex] (1.56 ± 0.02 ± 0.09) x 10-3
    - → K- K* ν).eps

    - → K- K* ν).gif

    τ- → K- K* π0 ν Belle arXiv:0808.1059 [hep-ex] (2.39 ± 0.46 ± 0.26) x 10-5

    τ- → K- η ν BaBar Phys.Rev.D83:032002,2011 (1.42 ± 0.11 ± 0.07) x 10-4
    - → K- η ν).eps

    - → K- η ν).gif

    Belle Phys.Lett.B672:209-218,2009 (1.58 ± 0.05 ± 0.09) x 10-4
    τ- → K- π0 η ν Belle Phys.Lett.B672:209-218,2009 (4.6 ± 1.1 ± 0.4) x 10-5
    - → K- π0 η ν).eps

    - → K- π0 η ν).gif

    τ- → KS0 π- η ν Belle Phys.Lett.B672:209-218,2009 (4.4 ± 0.7 ± 0.2) x 10-5
    - → KS0 π- η ν).eps

    - → KS0 π- η ν).gif

    τ- → K*- η ν Belle Phys.Lett.B672:209-218,2009 (1.34 ± 0.12 ± 0.09) x 10-4
    - → K*- η ν).eps

    - → K*- η ν).gif

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    Non-Strange Branching Fractions:

    Decay Mode Experiment Reference Results Averages
    - → π- ν)/(τ- → e- ν ν) BaBar Phys.Rev.Lett.105:051602,2010 (0.5945 ± 0.0014 ± 0.0061)
    - → π- ν).eps

    - → π- ν).gif

    τ- → π- π0 ν Belle Phys.Rev.D78:072006,2008 (25.24 ± 0.01 ± 0.39) X 10-2
    - → π- π0 ν).eps

    - → π- π0 ν).gif

    τ- → π- π- π+ ν (ex. KS0) BaBar Phys.Rev.Lett.100:011801,2008 (8.83 ± 0.01 ± 0.13) x 10-2
    - → π- π- π+ ν (ex. KS0)).eps

    - → π- π- π+ ν (ex. KS0)).gif

    Belle Phys.Rev.D81:113007,2010 (8.42 ± 0.01 +0.26-0.25) x 10-2
    τ- → π- π0 η ν Belle Phys.Lett.B672:209-218,2009 (1.35 ± 0.03 ± 0.07) x 10-3
    - → π- π0 η ν).eps

    - → π- π0 η ν).gif

    τ- → π- η ν (Second Class Current) Belle EPS2009 (4.4 ± 1.6 ± 0.8) x 10-5

    < 7.3 x 10-5 @ 90% C.L.
    τ- → f1(1285) π- ν [f1 → 2π-+] BaBar Phys.Rev.D72:072001,2005 (3.90 ± 0.70 ± 0.50) x 10-4
    - → f1(1285) π- ν).eps

    - → f1(1285) π- ν).gif

    τ- → f1(1285) π- ν [f1 → π- π+ η] BaBar Phys.Rev.D77:112002,2008 (3.19 ± 0.18 ± 1.00) x 10-4
    τ- → 3π-+ ν (ex. KS0) BaBar Phys.Rev.D72:072001,2005 (8.56 ± 0.05 ± 0.42) x 10-4
    - → 3π-+ ν (ex. KS0)).eps

    - → 3π-+ ν (ex. KS0)).gif

    τ- → 2π- π+ η ν BaBar Phys.Rev.D77:112002,2008 (1.60 ± 0.05 ± 0.11) x 10-4
    - → 2π- π+ η ν).eps

    - → 2π- π+ η ν).gif

    τ- → π- η’ ν (Second Class Current) Belle EPS2009 (-0.47 +3.97 -3.85 ± 0.26) x 10-6

    < 6.1 x 10-6 @ 90% C.L.
    τ- → π- η’ ν (Second Class Current) BaBar Phys.Rev.D77:112002,2008 < 7.2 x 10-6 @ 90% C.L.

    τ- → π- ω ν (Second Class Current) BaBar Phys.Rev.Lett.103:041802,2009 SCC/FCC < 0.69% @ 90% C.L.

    τ- → π- φ ν BaBar Phys.Rev.Lett.100:011801,2008 (3.42 ± 0.55 ± 0.25) x 10-5

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    Un-Constrained Global Fit:

    (Results for branching fractions (in %) from un-constrained fit).eps
    (Results for branching fractions (in %) from un-constrained fit).gif
    (Results for branching fractions (in %) from un-constrained fit).pdf

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    Unitarity Constrained Global Fit:

    (Results for branching fractions (in %) from unitarity constrained fit).eps
    (Results for branching fractions (in %) from unitarity constrained fit).gif
    (Results for branching fractions (in %) from unitarity constrained fit).pdf

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    Lepton Universality:

    (|gµ/ge|).eps
    (|gµ/ge|).gif

    (|gτ/gµ|).eps
    (|gτ/gµ|).gif

    (|gτ/ge|).eps
    (|gτ/ge|).gif

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    Extraction of |Vus|:

    (|Vus|).eps
    (|Vus|).gif

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    Results from Global Fit to Non-B-Factory Data:

    (Results from Global Fit to Non-B-Factory Data).ps
    (Results from Global Fit to Non-B-Factory Data).gif
    (Results from Global Fit to Non-B-Factory Data).pdf

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    Results from Global Fit including B-Factory Data:

    (Results from Global Fit including B-Factory Data).ps
    (Results from Global Fit including B-Factory Data).gif
    (Results from Global Fit including B-Factory Data).pdf

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    Lepton Flavour Violating Upper Limits:

    LFV Page
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    Search for CP Violation:

    Search for CP Violation in τ- → Ks π- ν decays at Belle arXiv:1101.0349 [hep-ex]
    (a) Values of CP asymmetry Acp in 4 mass bins:
    Mass region (GeV) Acp (10-3)
    0.625 - 0.890 7.9 ± 3.0 ± 2.8
    0.890 - 1.110 1.8 ± 2.1 ± 1.4
    1.110 - 1.420 -4.6 ± 7.2 ± 1.7
    1.420 - 1.775 -2.3 ± -19.1 ± -5.5
    (b) Upper limit for CP violating coupling constant Im(ηs) < 0.026 at 90% CL.
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    Mass Spectrum Data

    (a) τ- → π- π0 ν decays at Belle Phys.Rev.D78:072006,2008
    README: README.txt
    Mass Spectrum: TableV.dat
    Mass Spectrum: TableV-emat.dat
    Pion Form Factor: TableVI.dat
    Pion Form Factor: TableVI-emat.dat

    (b) τ- → h- h- h+ν decays at Belle Phys.Rev.D81:113007,2010
    Unfolded M(hhh) mass spectrum: tau_hhhnu_spec.txt
    Covariance Matrix: tau_hhhnu_cov.txt

    (c) τ- → Ks π- ν decays at Belle Phys.Lett.B654:65-73,2007
    Acceptance corrected mass spectrum: tau_kspinu.dat
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    This page was maintained by Swagato Banerjee and was last updated