Measurement of the pion branching ratio at TRIUMF

C. Malbrunot, A. A. Aguilar-Arevalo, M. Aoki, M. Blecher, D. I. Britton, D. A. Bryman, S. Chen, J. Comfort, M. Ding, L. Doria, P. Gumplinger, A. Hussein, Y. Igarashi, S. Ito, S. H. Kettell, Y. Kuno, L. Kurchaninov, L. Littenberg, T. Numao, A. SherT. Sullivan, D. Vavilov, M. Yoshida

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)


The branching ratio of pion decays, R=Γ(π +→e +ν e+→e +ν eγ)/Γ(π +→μ +ν μ+→μ +ν μγ is one of the most accurately calculated decay processes involving hadrons and has provided one of the most stringent tests of the hypothesis of electron-muon universality in weak interactions. The current experimental branching ratio R exp=(1.230±0.004)×10 -4 is 40 times less precise than the theoretical prediction R SM=1.2352(1)10 -4. The TRIUMF PIENU experiment aims at measuring the pion branching ratio with a precision improved by at least a factor five.

Original languageEnglish
Title of host publication19th Particles and Nuclei International Conference, PANIC11
Number of pages3
Publication statusPublished - 2012
Externally publishedYes
Event19th Particles and Nuclei International Conference, PANIC11 - Cambridge, MA, United States
Duration: Jul 24 2011Jul 29 2011

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Other19th Particles and Nuclei International Conference, PANIC11
Country/TerritoryUnited States
CityCambridge, MA


  • Pion branching ratio
  • Standard Model test
  • universality

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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