Observation of tau(-) -> pi(-)nu(tau)e(+)e(-) and search for tau(-) -> pi(-)nu(tau)mu(+)mu(-)
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F19%3A10407960" target="_blank" >RIV/00216208:11320/19:10407960 - isvavai.cz</a>
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=cKbN7NnwZK" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=cKbN7NnwZK</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1103/PhysRevD.100.071101" target="_blank" >10.1103/PhysRevD.100.071101</a>
Alternative languages
Result language
angličtina
Original language name
Observation of tau(-) -> pi(-)nu(tau)e(+)e(-) and search for tau(-) -> pi(-)nu(tau)mu(+)mu(-)
Original language description
We present the first measurements of branching fractions of rare tau-lepton decays, tau(-) -> pi(-)nu(tau)l(+)l(-) (l = e or mu), using a data sample corresponding to 562 fb(-1) collected at a center-of-mass energy of 10.58 GeV with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The tau(-) -> pi(-)nu(tau)e(+)e(-) decay is observed for the first time with 7.0 sigma significance. The partial branching fraction determined by the structure-dependent mechanisms mediated by either a vector or an axial-vector current for the mass region M-pi ee > 1.05 GeV/c(2) is measured to be B(tau(-) -> pi(-)nu(tau)e(+)e(-))[M pi-e+e- > 1.05 GeV/c(2)] = (5.90 +/- 0.53 +/- 0.85 +/- 0.11) x 10(-6), where the first uncertainty is statistical, the second is systematic, and the third is due to model dependence. In the full phase space, due to the different detection efficiencies for the structure-dependent mechanisms mediated by axial-vector and vector currents, the branching fraction varies from B-A(tau(-) -> pi(-)nu(tau)e(+)e(-)) = (1.46 +/- 0.13 +/- 0.21) x 10(-5) to B-V(tau(-) -> pi(-)nu(tau)e(+)e(-)) = (3.01 +/- 0.27 +/- 0.43) x 10(-5), respectively. An upper limit is set on the branching fraction of the tau(-) -> pi(-)nu(tau)mu(+)mu(-) decay, B(tau(-) -> pi(-)nu(tau)mu(+)mu(-)) < 1.14 x 10(-5), at the 90% confidence level.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10303 - Particles and field physics
Result continuities
Project
<a href="/en/project/LTT17020" target="_blank" >LTT17020: Study of Beyond Standard Model Physics with the International Experiment Belle II in Japan</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2019
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Physical Review D
ISSN
2470-0010
e-ISSN
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Volume of the periodical
100
Issue of the periodical within the volume
7
Country of publishing house
US - UNITED STATES
Number of pages
9
Pages from-to
071101
UT code for WoS article
000490172200001
EID of the result in the Scopus database
2-s2.0-85074909636