Improved measurement of the branching fractions for J/ψ→γπ⁰, γη and γη^′

2023/08/26 by BESIII Collaboration, М. Н. Ачасов, Ablikim, M. +703
Physics and Astronomy · #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #High-Energy Particle Collisions Research

paper · pdf · doi:10.48550/arxiv.2308.13725

Abstract

Using a data sample of (1.0087± 0.0044)× 10¹⁰ J/ψ events collected with the BESIII detector, the decays of J/ψ→γπ⁰ (η, η^′)→γγγ are studied. Newly measured branching fractions are B(J/ψ→γπ⁰)=(3.34± 0.02± 0.09)× 10^-5, B(J/ψ→γη)=(1.096± 0.001±0.019)× 10^-3 and B(J/ψ→γη^′)=(5.40± 0.01±0.11)× 10^-3, where the first uncertainties are statistical and the second are systematic. These results are consistent with the world average values within two standard deviations. The ratio of partial widths Γ(J/ψ→γη^′)/Γ(J/ψ→γη) is measured to be 4.93 ± 0.13. The singlet-octet pseudoscalar mixing angle θ_P is determined to be θ_P = -(22.11 ±0.26)^∘ or -(19.34 ± 0.34)^∘ with two different phenomenological models.

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