Semi-analytical results for e+e-→ J/ψ+ Xnon cc̅ up to 𝒪(αs v2) at B factories
Abstract
Within the NRQCD factorization framework, we investigate the color-singlet contribution to e+e- → J/ψ+ Xnon cc̅ at B factories, computing the 𝒪(αs), 𝒪(v2), and 𝒪(αs v2) corrections to both the unpolarized cross section and the J/ψ angular distribution. The 𝒪(αs v2) correction is obtained for the first time, and the validity of NRQCD factorization at this order is explicitly verified. Using the differential equation method, the short-distance coefficients are obtained as asymptotic expansions in r = mc/√s up to r40, which reproduce exact results with high precision at B factory energies, achieving relative errors around 10−14 for the cross section and around 10−7 for the angular distribution. Notably, with the same input parameters, our 𝒪(αs) and 𝒪(v2) corrections are consistent with those reported in the literature. Phenomenologically, the 𝒪(αs) correction (with μR=√s/2) reaches about 50% of the leading-order cross section, while the 𝒪(v2) and 𝒪(αs v2) corrections are accidentally small. After including feeddown contributions from ψ(2S), the predicted cross section 0.523−0.197+0.285 pb agrees with the {\tt Belle} measurement within uncertainties. However, the predicted angular distribution parameter 0.120−0.036+0.041 deviates from the experimental value 5.71± 2.51 by more than 2σ, calling for further experimental and theoretical investigations.
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BibTeX
@misc{li2026semianalytical,
title = {{Semi-analytical results for $e^+e^-\to J/ψ+ X_\rm non\,c\barc$ up to $\mathcalO(α_s v^2)$ at B factories}},
author = {Cong Li and Hao-Yang Liu and Xu-Dong Huang and Wen-Long Sang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2606.17827},
eprint = {2606.17827},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.17827},
}
RIS
TY - UNPB
TI - Semi-analytical results for e^+e^-→ J/ψ+ X_non cc̅ up to 𝒪(α_s v^2) at B factories
AU - Cong Li
AU - Hao-Yang Liu
AU - Xu-Dong Huang
AU - Wen-Long Sang
PY - 2026
DA - 2026/09/09
PB - arXiv
DO - 10.48550/arxiv.2606.17827
UR - https://arxiv.org/abs/2606.17827
AB - Within the NRQCD factorization framework, we investigate the color-singlet contribution to e^+e^- → J/ψ+ X_non cc̅ at B factories, computing the 𝒪(α_s), 𝒪(v^2), and 𝒪(α_s v^2) corrections to both the unpolarized cross section and the J/ψ angular distribution. The 𝒪(α_s v^2) correction is obtained for the first time, and the validity of NRQCD factorization at this order is explicitly verified. Using the differential equation method, the short-distance coefficients are obtained as asymptotic expansions in r = m_c/√s up to r^40, which reproduce exact results with high precision at B factory energies, achieving relative errors around 10^−14 for the cross section and around 10^−7 for the angular distribution. Notably, with the same input parameters, our 𝒪(α_s) and 𝒪(v^2) corrections are consistent with those reported in the literature. Phenomenologically, the 𝒪(α_s) correction (with μ_R=√s/2) reaches about 50% of the leading-order cross section, while the 𝒪(v^2) and 𝒪(α_s v^2) corrections are accidentally small. After including feeddown contributions from ψ(2S), the predicted cross section 0.523_−0.197^+0.285 pb agrees with the {\tt Belle} measurement within uncertainties. However, the predicted angular distribution parameter 0.120_−0.036^+0.041 deviates from the experimental value 5.71± 2.51 by more than 2σ, calling for further experimental and theoretical investigations.
ER -