Precision measurement of the ratio B(Υ(3S)→τ⁺τ^-)/B(Υ(3S)→μ⁺μ^-)

2021/05/19 by Miller, Caleb
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex)

paper · doi:10.48550/arxiv.2105.08921

Abstract

The BaBar collaboration has measured the ratio R_τμ^Υ(3S)=B(Υ(3S)→τ⁺τ^-)/B(Υ(3S)→μ⁺μ^-) with a high level of precision. This measurement utilized a 28 fb^-1 dataset collected at a center-of-mass energy of 10.355 GeV. The measured ratio, R_τμ^Υ(3S), is measured to be R_τμ^Υ(3S)=0.966±0.008_\textrmstat±0.014_\textrmsyst. This value is within 2 standard deviations of the standard model prediction R_τμ^Υ(3S)=0.9948. The new measurement is approximately a factor of 6× more precise than the only prior measurement. This increased precision is in part due to a more complete analysis of the radiative tail in the Υ(3S) decay, in addition to a significant increase in statistics.

Related

• Precision tests via radiative μ and τ leptonic decays
• Measurement of the Υ(1S), Υ(2S), and Υ(3S) differential cross sections in pp collisions at √(s)=13.6 TeV
• Measurement of the ratio of the B_c⁺ → J/ψτ⁺ν_τ and B_c⁺ → J/ψ μ⁺ν_μ branching fractions using three-prong τ lepton decays
• Measurement of radiative tau decays tau -> l gamma nu anti-nu at BaBar
• Measurement of the branching ratio of B⁰ → D^*+ τ^- ν_τ relative to B⁰ → D^*+ ℓ^- ν_ℓ decays with a semileptonic tagging method