2025/10/24 by Wen-Long Sang, Feng Feng, Sang, Wen-Long +9
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2510.21350
openalex publication_date 2025/10/24 · openalex created_date 2025/10/28 · openalex updated_date 2026/07/28
We report the calculation of the process e+ e- → J/ψJ/ψ up to next-to-next-to-leading order (NNLO) at a center-of-mass (CM) energy of √(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 αs and lowest order in velocity. In this optimized scheme, both \cal O(αs) and \cal O(α2s) 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 Belle 2, the prospects for observing exclusive double J/ψ production are very promising.