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Title: Precision Measurements of Tau Lepton Decays

Abstract

Using data collected with the BABAR detector at the SLAC PEP-II electron-positron storage ring operating at a centre-of-mass energy near 10.58 GeV, the branching fractions B(τ- → π-π-π+ντ) =(8.83±0.01±0.13)%, B(τ- → K-π-π+ντ) =(0.273± 0.002 ± 0.009)%, B(τ- → K-π-K+ντ) =(0.1346 ± 0.0010 ± 0.0036)%, and B(τ- → K-K-K+ντ) =(1.58 ± 0.13 ± 0.12) × 10-5 are measured where the uncertainties are statistical and systematic, respectively. The invariant mass distribution for the τ- → π-π-π+ντ , τ- → K-π-π+ντ , τ- → K-π-K+ντ and τ- → K-K-K+ντ decays are unfolded to correct for detector effects. A measurement of B(τ- → φπ-ντ ) =(3.42±0.55±0.25)×10-5, a measurement of B(τ- → φK-ντ) =(3.39±0.20±0.28)× 10-5 and an upper limit on B(τ- → K-K-K+ντ [ex.φ]) ≤ 2.5 × 10-6@90%CL are determined from a binned maximum likelihood fit of the τ- → K-π-K+ντ and τ- → K-K-K+ντ K+K- invariant mass distributions. The branching ratio B(τ-→K-ντ )/ B(τ-→π-ντ ) is measured to be (6.531±0.056±0.093)×10-2 from which |Vus| is determined to be 0.2255 ± 0.0023. The branching ratio B(τ-→μ-ντ $$\bar{v}$$μ)/ B(τ-→e-ντ $$\bar{v}$$e) =(9.796 ± 0.016 ± 0.035) × 10-1 is measured enabling a precision test of the Standard Model assumption of charged current lepton universality, gμ ge =1.0036 ±more » 0.0020. The branching ratios B(τ-→K-ντ ) /B(τ-→e-ντ $$\bar{v}$$e) =(3.882 ± 0.032 ± 0.057) × 10-2, and B(τ-→π-ντ ) /B(τ-→e-ντ $$\bar{v}$$e) =(5.945 ± 0.014 ± 0.061) × 10-1 are measured which provide additional tests of charged current lepton universality, gτ/gμ π = 0.9856 ± 0.0057 and gτ/gμ K = 0.9827 ± 0.0086 which can be combined to give gτ/gμ π/K = 0.9850 ± 0.0054 . Any deviation of these measurements from the expected Standard Model values would be an indication of new physics.« less

Authors:
 [1]
  1. Univ. of Victoria, BC (Canada)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
969233
Report Number(s):
SLAC-R-936
TRN: US1000264
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Thesis/Dissertation
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACCURACY; BRANCHING RATIO; CHARGED CURRENTS; LEPTONS; MASS DISTRIBUTION; MAXIMUM-LIKELIHOOD FIT; PHYSICS; STANDARD MODEL; STANFORD LINEAR ACCELERATOR CENTER; STORAGE RINGS; TAU PARTICLES; Experiment-HEP; HEPEX

Citation Formats

Nugent, Ian M. Precision Measurements of Tau Lepton Decays. United States: N. p., 2008. Web. doi:10.2172/969233.
Nugent, Ian M. Precision Measurements of Tau Lepton Decays. United States. https://doi.org/10.2172/969233
Nugent, Ian M. 2008. "Precision Measurements of Tau Lepton Decays". United States. https://doi.org/10.2172/969233. https://www.osti.gov/servlets/purl/969233.
@article{osti_969233,
title = {Precision Measurements of Tau Lepton Decays},
author = {Nugent, Ian M.},
abstractNote = {Using data collected with the BABAR detector at the SLAC PEP-II electron-positron storage ring operating at a centre-of-mass energy near 10.58 GeV, the branching fractions B(τ- → π-π-π+ντ) =(8.83±0.01±0.13)%, B(τ- → K-π-π+ντ) =(0.273± 0.002 ± 0.009)%, B(τ- → K-π-K+ντ) =(0.1346 ± 0.0010 ± 0.0036)%, and B(τ- → K-K-K+ντ) =(1.58 ± 0.13 ± 0.12) × 10-5 are measured where the uncertainties are statistical and systematic, respectively. The invariant mass distribution for the τ- → π-π-π+ντ , τ- → K-π-π+ντ , τ- → K-π-K+ντ and τ- → K-K-K+ντ decays are unfolded to correct for detector effects. A measurement of B(τ- → φπ-ντ ) =(3.42±0.55±0.25)×10-5, a measurement of B(τ- → φK-ντ) =(3.39±0.20±0.28)× 10-5 and an upper limit on B(τ- → K-K-K+ντ [ex.φ]) ≤ 2.5 × 10-6@90%CL are determined from a binned maximum likelihood fit of the τ- → K-π-K+ντ and τ- → K-K-K+ντ K+K- invariant mass distributions. The branching ratio B(τ-→K-ντ )/ B(τ-→π-ντ ) is measured to be (6.531±0.056±0.093)×10-2 from which |Vus| is determined to be 0.2255 ± 0.0023. The branching ratio B(τ-→μ-ντ $\bar{v}$μ)/ B(τ-→e-ντ $\bar{v}$e) =(9.796 ± 0.016 ± 0.035) × 10-1 is measured enabling a precision test of the Standard Model assumption of charged current lepton universality, gμ ge =1.0036 ± 0.0020. The branching ratios B(τ-→K-ντ ) /B(τ-→e-ντ $\bar{v}$e) =(3.882 ± 0.032 ± 0.057) × 10-2, and B(τ-→π-ντ ) /B(τ-→e-ντ $\bar{v}$e) =(5.945 ± 0.014 ± 0.061) × 10-1 are measured which provide additional tests of charged current lepton universality, gτ/gμ π = 0.9856 ± 0.0057 and gτ/gμ K = 0.9827 ± 0.0086 which can be combined to give gτ/gμ π/K = 0.9850 ± 0.0054 . Any deviation of these measurements from the expected Standard Model values would be an indication of new physics.},
doi = {10.2172/969233},
url = {https://www.osti.gov/biblio/969233}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 2008},
month = {Tue Jan 01 00:00:00 EST 2008}
}

Thesis/Dissertation:
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