We study $e^{+}e^{-} \to J/\psi+\eta_c+X$ at next-to-leading order (NLO) in $\alpha_s$ within the nonrelativistic QCD (NRQCD) framework to assess the color-octet (CO) mechanism at low energies. QCD corrections significantly enhance both color-singlet (CS) and CO leading-order results, with non-negligible QED-diagram contributions to the CS channel. At $\Upsilon(4S)$, CO terms increase the inclusive cross section by $20\%$--$30\%$, and the enhancement grows rapidly with $\sqrt{s}$, yielding an energy dependence distinct from CS predictions and providing a sensitive test of NRQCD. Including $\psi(2S)$ feed-down further amplifies the NRQCD prediction by about $40\%$ at $\Upsilon(4S)$. With Belle's reconstruction of $J/\psi \to \mu^+\mu^-$ and six $\eta_c$ decay channels, the process shows promising potential for observation.
We present a global determination of the six long-distance matrix elements (LDMEs) within non-relativistic QCD (NRQCD) appearing in the production of prompt $J/\psi$ up to $\mathcal{O}(v^2)$ using high-$P_T$ LHC data for direct and feed-down contributions from $\chi_c$ and $\psi(2S)$. Using a leading-power fragmentatio...
V. Bertone, J. Lansberg, K. Lynch et al.· 0 citations
The proposed high-luminosity Super Tau-Charm Facility (STCF) offers a clean experimental environment for threshold studies of exotic hadrons. In this Letter, we evaluate the expected significance for the fully-charmed vector tetraquark candidate $T_{4c}$ in the $e^+e^- \to \eta_c J/\psi$ channel at the STCF. Using Mont...
Zhu-Juan Dong, Xiao-Rong Zhou, Xiao-Rui Lv et al.· 0 citations
Motivated by the recent CMS data on a family of $2^{++}$ states from $J/\psi J/\psi$ mass spectrum, we determine the masses of the $2^{++}$ $J/\psi J/\psi$ molecule and $cc\bar c\bar c$ states, by using (for the first time) the two lowest QCD Laplace Sum Rules (LSR) moment-ratios within the standard optimization criter...
S. Narison, A. Rabemananjara, D. Rabetiarivony· 0 citations
Using $2712.4 \pm 14.3$ million $\psi(3686)$ events collected with the BESIII detector, the $\Lambda\bar{\Lambda}$ system produced in $\psi(3686)$ radiative decays is studied. A model-independent partial wave analysis reveals a significant threshold enhancement structure dominated by the $^1S_0$ and $^3P_0$ partial wav...
Besiii Collaboration M. Ablikim, M. N. Achasov, P. Adlarson et al.· 0 citations
We study radiative double-charmonium production, $e^+e^-\to HH\gamma$ with $H=J/\psi$ and $\eta_c$, at $\sqrt{s}=10.58~{\rm GeV}$, including a possible tensor contribution from the fully charmed state $X(6900)$. The nonresonant amplitudes are calculated within the color-singlet non-relativistic QCD framework, while the...
Meng Jia, Yi-Jie Li, Guang-Hua Xu et al.· 1 citation
In this paper, we present a comprehensive analysis of the next-to-next-to-leading-order (NNLO) QCD corrections to the exclusive processes $e^{+}e^{-}\to J/\psi+\eta_{c}$, $e^{+}e^{-}\to J/\psi+\chi_{cJ}$, $e^{+}e^{-}\to \eta_{c}+\gamma$, and $e^{+}e^{-}\to \chi_{cJ}+\gamma$ $(J=0,1,2)$ at the $B$ factories, comparing p...
Xu-Dong Huang, Jian-Xiong Wang· 2 citations· ⚡1
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