Measurement of the Branching Fraction of \boldmathψ(2S) → γπ⁰

2024/08/07 by BESIII Collaboration, M. Ablikim, М. Н. Ачасов +744
Chemistry · Mathematics · #Biochemistry #Branching (polymer chemistry) #Chemistry #Markov Chains and Monte Carlo Methods #Nuclear physics #Particle physics #Physics #Pi #Stochastic processes and statistical mechanics #advanced mathematical theories

paper · pdf · doi:10.48550/arxiv.2408.03531

openalex publication_date 2024/08/07 · openalex created_date 2024/10/16 · openalex updated_date 2026/08/01

Abstract

Based on (2712.4±14.1)×10⁶~ψ(2S) events, 7.9 fb^-1 ψ(3773) data, and 0.8 fb^-1 off-resonance data samples collected with the BESIII detector, we measure the branching fraction of ψ(2S)→γπ⁰ and e⁺e^-→γπ⁰ form factor at momentum transfers Q²∼13 GeV². The e⁺e^-→γπ⁰ cross section is fitted with considering the interference between the ψ(2S) and continuum amplitudes and two solutions are found, \cal B=3.74×10^-7 with ϕ=3.93 rad and \cal B=7.87×10^-7 with ϕ=2.08 rad. Here, \cal B is the branching fraction of ψ(2S)→γπ⁰ and ϕ is the relative phase angle between the ψ(2S) and continuum amplitudes. Due to insufficient off-resonance data, the branching fraction \cal B(ψ(2S)→γπ⁰) is determined to be in the range [2.7, 9.7]×10^-7 within one standard deviation of the contour region.

Related

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