Optimized QCD two-loop correction to exclusive double $J/ψ$ production at B factories
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| Main Authors: | , , , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866917039681044480 |
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| author | Sang, Wen-Long Feng, Feng Jia, Yu Mo, Zhewen Pan, Jichen Zhang, Jia-Yue |
| author_facet | Sang, Wen-Long Feng, Feng Jia, Yu Mo, Zhewen Pan, Jichen Zhang, Jia-Yue |
| contents | We report the calculation of the process $e^+ e^- \to J/ψJ/ψ$ up to next-to-next-to-leading order (NNLO) at a center-of-mass (CM) energy of $\sqrt{s}=10.58$ GeV. We employ an improved NRQCD factorization approach, decomposing the amplitude into photon-fragmentation and non-fragmentation components. The fragmentation contribution is determined using the measured $J/ψ$ decay constant, while the interference and non-fragmentation parts are computed at NNLO in $α_s$ and lowest order in velocity. In this optimized scheme, both ${\cal O}(α_s)$ and ${\cal O}(α^2_s)$ corrections in the interference part are positive and exhibit good convergence. The non-fragmentation part is numerically insignificant. Our results indicate that with the projected 50 ${\rm ab}^{-1}$ dataset at \texttt{Belle 2}, the prospects for observing exclusive double $J/ψ$ production are very promising. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_21350 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Optimized QCD two-loop correction to exclusive double $J/ψ$ production at B factories Sang, Wen-Long Feng, Feng Jia, Yu Mo, Zhewen Pan, Jichen Zhang, Jia-Yue High Energy Physics - Phenomenology We report the calculation of the process $e^+ e^- \to J/ψJ/ψ$ up to next-to-next-to-leading order (NNLO) at a center-of-mass (CM) energy of $\sqrt{s}=10.58$ GeV. We employ an improved NRQCD factorization approach, decomposing the amplitude into photon-fragmentation and non-fragmentation components. The fragmentation contribution is determined using the measured $J/ψ$ decay constant, while the interference and non-fragmentation parts are computed at NNLO in $α_s$ and lowest order in velocity. In this optimized scheme, both ${\cal O}(α_s)$ and ${\cal O}(α^2_s)$ corrections in the interference part are positive and exhibit good convergence. The non-fragmentation part is numerically insignificant. Our results indicate that with the projected 50 ${\rm ab}^{-1}$ dataset at \texttt{Belle 2}, the prospects for observing exclusive double $J/ψ$ production are very promising. |
| title | Optimized QCD two-loop correction to exclusive double $J/ψ$ production at B factories |
| topic | High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2510.21350 |