The pion branching ratio, Rπ = γ(π+→e+ve+π+→e+veϒ) γ(π+→μ+, vμ+π+→μ+vμϒ) provides a sensitive test of lepton universality and constraints on many new physics scenarios. The theoretical uncertainty on the Standard Model prediction of Rπ is 0.02%, a factor of twenty smaller than the experimental uncertainty. The analysis of a subset of data taken by the PIENU experiment will be presented. The result, Rπ = (1.2344±0.0023(stat) ±0.0019(syst)) 10-4, is consistent with the Standard Model prediction and represents a 0.1% constraint on lepton non-universality.
|Journal||Proceedings of Science|
|Publication status||Published - 2016|
|Event||13th International Conference on Heavy Quarks and Leptons, HQL 2016 - Blacksburg, United States|
Duration: May 22 2016 → May 27 2016
ASJC Scopus subject areas