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Sang WL, Feng F, Jia Y, Mo Z, Pan J, Zhang JY. Optimized O(α_{s}^{2}) Correction to Exclusive Double-J/ψ Production at B Factories. PHYSICAL REVIEW LETTERS 2023; 131:161904. [PMID: 37925731 DOI: 10.1103/physrevlett.131.161904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/13/2023] [Accepted: 09/21/2023] [Indexed: 11/07/2023]
Abstract
The failure of observing the e^{+}e^{-}→J/ψJ/ψ events at B factories to date is often attributed to the significant negative order-α_{s} correction. In this work we compute the O(α_{s}^{2}) correction to this process for the first time. The magnitude of the next-to-next-to-leading order (NNLO) perturbative correction is substantially negative so that the standard nonrelativistic QCD prediction would suffer from an unphysical, negative cross section. This dilemma may be traced in the fact that the bulk contribution of the fixed-order radiative corrections stems from the perturbative corrections to the J/ψ decay constant. We thus implement an improved nonrelativistic QCD factorization framework, by decomposing the amplitude into the photon-fragmentation piece and the nonfragmentation piece. With the measured J/ψ decay constant as input, which amounts to resumming a specific class of radiative and relativistic corrections to all orders, the fragmentation-induced production rate can be predicted accurately and serves a benchmark prediction. The nonfragmentation type of the amplitude is then computed through NNLO in α_{s} and at lowest order in velocity. Both the O(α_{s}) and O(α_{s}^{2}) corrections in the interference term become positive and exhibit a decent convergence behavior. Our finest prediction is σ(e^{+}e^{-}→J/ψJ/ψ)=2.13_{-0.06}^{+0.30} fb at sqrt[s]=10.58 GeV. With the projected integrated luminosity of 50 ab^{-1}, the prospect to observe this exclusive process at Belle 2 experiment appears to be bright.
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Affiliation(s)
- Wen-Long Sang
- School of Physical Science and Technology, Southwest University, Chongqing 400700, China
| | - Feng Feng
- Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences, Beijing 100049, China
- China University of Mining and Technology, Beijing 100083, China
| | - Yu Jia
- Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences, Beijing 100049, China
- School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhewen Mo
- Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences, Beijing 100049, China
- School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jichen Pan
- Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences, Beijing 100049, China
- School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jia-Yue Zhang
- Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences, Beijing 100049, China
- School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
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