Abstract
We report the measurement of the two-photon decay width of χc2(1P) in two-photon processes at the Belle experiment. We analyze the process γγ → χc2(1P) → J/ψγ, J/ψ → ℓ+ℓ− (ℓ = e 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 χc2(1P) and the branching fraction is determined to be \( {\Gamma}_{\gamma \gamma}\left({\chi}_{c2}(1P)\right)\mathcal{B}\left({\chi}_{c2}(1P)\to J/\psi \gamma \right)\mathcal{B}\left(J/\psi \to {\ell}^{+}{\ell}^{-}\right)=14.8\pm 0.3\left(\textrm{stat}.\right)\pm 0.7\left(\textrm{syst}.\right) \) eV, which corresponds to Γγγ(χc2(1P)) = 653 ± 13(stat.) ± 31(syst.) ± 17(B.R.) eV, where the third uncertainty is from \( \mathcal{B} \)(χc2(1P) → J/ψγ) and \( \mathcal{B} \)(J/ψ → ℓ+ℓ−).
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The Belle collaboration., Seino, Y., Hayasaka, K. et al. Measurement of two-photon decay width of χc2(1P) in γγ → χc2(1P) → J/ψγ at Belle. J. High Energ. Phys. 2023, 160 (2023). https://doi.org/10.1007/JHEP01(2023)160
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DOI: https://doi.org/10.1007/JHEP01(2023)160