Measurement of two-photon decay width of χ_c2(1P) in γγ→ χ_c2(1P) → J/ψγ at Belle

2022/08/09 by The Belle Collaboration, Seino, Y., Hayasaka, K. +194
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex)

paper · doi:10.48550/arxiv.2208.04477

Abstract

We report the measurement of the two-photon decay width of χ_c2(1P) in two-photon processes at the Belle experiment. We analyze the process γγ→ χ_c2(1P) → J/ψγ, J/ψ→ ℓ⁺ ℓ^- (ℓ = e \rm or μ) using a data sample of 971 fb^-1 collected with the Belle detector at the KEKB e⁺ e^- collider. In this analysis, the product of the two-photon decay width of χ_c2(1P) and the branching fraction is determined to be Γ_γγ(χ_c2(1P)) B( χ_c2(1P) → J/ψ γ)B( J/ψ→ ℓ⁺ℓ^- ) = \rm 14.8 ± \rm 0.3(\rm stat.) ± \rm 0.7(\rm syst.) eV, which corresponds to Γ_γγ(χ_c2(1P)) = 653 ± 13(stat.) ± 31(syst.) ± 17(B.R.) eV, where the third uncertainty is from B( χ_c2(1P) → J/ψ γ) and B( J/ψ→ ℓ⁺ℓ^- ).

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