Test of Lepton Universality in Υ(1S) Decays at BABAR
Author(s)Fisher, Peter H.; Dujmic, Denis; Cowan, Ray Franklin; Sciolla, Gabriella; Yamamoto, R. K.; Zhao, M.; ... Show more Show less
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The ratio Rtau mu(Υ(1S))=ΓΥ(1S)-->tau+tau-/GammaΥ(1S)-->mu+mu- is measured using a sample of (121.8±1.2)×10[superscript 6]Υ(3S) events recorded by the BABAR detector. This measurement is intended as a test of lepton universality and as a search for a possible light pseudoscalar Higgs boson. In the standard model (SM) this ratio is expected to be close to 1. Any significant deviations would violate lepton universality and could be introduced by the coupling to a light pseudoscalar Higgs boson. The analysis studies the decays Υ(3S)-->Υ(1S)pi+pi-, Υ(1S)→l+l-, where l=mu, tau. The result, Rtau mu(Υ(1S))=1.005±0.013(stat)±0.022(syst), shows no deviation from the expected SM value, while improving the precision with respect to previous measurements.
DepartmentMassachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Laboratory for Nuclear Science
Physical Review Letters
American Physical Society
BABAR Collaboration et al. “Test of Lepton Universality in Upsilon (1S) Decays at BABAR.” Physical Review Letters 104.19 (2010): 191801. © 2010 The American Physical Society.
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