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The ϕ-meson leptonic widths, Γee and Γμμ, are obtained, respectively, from the e+e− forward–backward asymmetry and the μ+μ− cross section around the ϕ-mass energy. We find Γee=1.32±0.05±0.03 keV and ΓeeΓμμ=1.320±0.018±0.017 keV. These results, compatible with Γee=Γμμ, provide a precise test of lepton universality. Combining the two results gives Γℓℓ(ϕ)=1.320±0.023 keV.
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