Get started
Work

Semi-analytical results for $$ {e}^{+}{e}^{-}\to J/\psi +{X}_{\mathrm{non}\ c\overline{c}} $$ up to 𝒪(αsv2) at B factories

Year: 2026
Type: article
Abstract: A bstract Within the NRQCD factorization framework, we investigate the color-singlet contribution to $$ {e}^{+}{e}^{-}\to J/\psi +{X}_{\mathrm{non}\ c\overline{c}} $$ e + e − → J / ψ + X non c c ¯ 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 $$ r={m}_c/\sqrt{s} $$ 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 $$ {\mu}_R=\sqrt{s}/2 $$ 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 (2 S ), the predicted cross section $$ {0.523}_{-0.197}^{+0.285} $$ 0.523 − 0.197 + 0.285 pb agrees with the Belle measurement within uncertainties. However, the predicted angular distribution parameter $$ {0.120}_{-0.036}^{+0.041} $$ 0.120 − 0.036 + 0.041 deviates from the experimental value 5.71 ± 2.51 by more than 2 σ , calling for further experimental and theoretical investigations.
DOI: 10.1007/jhep09(2026)128
Language: English
Open Access status: diamond
OpenAlex ID: W7212238464
FWCI: 2.545
Cites: 69
Cited by: 3
Related to: 10