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Search for Lepton Universality Violation Using Υ (3S) Decays

The measurement of the ratio of the branching fractions of Υ (3S) decays into τ leptons over dimuons (R τ /μ = B(Υ (3S) → τ + τ − )/B(Υ (3S) → μ + μ − )) is a test of lepton universality. A violation of lepton universality would be evidence of new physics (and possibly of a light CP-odd Higgs boson). A sample of Υ (3S) decays (2.408 fb −1 ) collected with the B A B AR detector at the SLAC National Accelerator Laboratory was used to determine that the ratio R τ /μ is R τ /μ = 1.0385 ± 0.034 ± 0.019. Using the remaining blinded data sample (corresponding to an integrated luminosity of 25.6 fb −1 ) the estimated statistical sensitivity will be 1.1 % and the estimated systematic uncertainty of R τ /μ is 1.9 %. Prior to this work, previous measurements of R τ /μ had an estimated total precision of 10 %. / Graduate

Identiferoai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/5809
Date23 December 2014
CreatorsKing, Gregory
ContributorsRoney, J. Michael
Source SetsUniversity of Victoria
LanguageEnglish, English
Detected LanguageEnglish
TypeThesis
RightsAvailable to the World Wide Web, http://creativecommons.org/licenses/by-nc-nd/2.5/ca/, http://creativecommons.org/licenses/by-nc-nd/2.5/ca/

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