Related papers: Determination of color-octet matrix elements from …
Basing on the branching fractions of J/\psi \to VP from different experiments, we investigate on the properties of the coupling constants of J/\psi \to VP decays with a model-dependent approach. We find that the octet coupling constant,…
We investigate the theoretical uncertainties of $P$-wave charmonium decays into two pions, $\chi_{\c J}\rightarrow \pi^+\pi^-$, $\pi^0\pi^0$. Constraining the pion distribution-amplitude from the recent precise data on $F_{\pi\gamma}(Q^2)$,…
The $e^+e^- \to \pi^+ \pi^- \pi^0 \chi_{bJ}$ ($J=0,~1,~2$) processes are studied using a 118~fb$^{-1}$ data sample collected at a center-of-mass energy of 10.867 GeV, in the $\Upsilon(10860)$ energy range, with the Belle detector. The…
The study of $J/\psi$ photoproduction at low energies has consequences for the understanding of multiple aspects of nonperturbative QCD, ranging from mechanical properties of the proton, to the binding inside nuclei, and the existence of…
Up to the next-leading order (NLO) of quantum chromodynamics (QCD), the process $e^+e^-\to J/\psi +X$ with the center-of-mass (CM) energy range from 3.7 to 10.6 GeV is calculated. At 10.6 GeV, the results is consistent with the experiment…
We investigate $e^+ e^- \to t\bar t$ by taking into account wave function distortion effects in the near-threshold region and interpolating the correction factor to the high-energy perturbative QCD region. The strong color attraction…
The cross section of the process $e^+e^-\to\pi^+\pi^-\pi^0$ is measured with a precision of 1.6% to 25% in the energy range between $0.7$ and 3.0 GeV using the Initial State Radiation method. A data set with an integrated luminosity of…
We present a systematical study on the prompt $J/\psi$ production in association with a $c\bar{c}$ pair via the process, $\gamma\gamma \to H(c\bar{c}) +c+\bar{c}$, within the framework of non-relativistic QCD at the future high-energy…
Motivated by the recent observation of double charm quark pair production by the Belle Collaboration, we calculate the complete ${\cal O}(\alpha_{s}^{2})$ inclusive production cross sections for $\eta_{c}$, $J/\psi$, and $\chi_{cJ}$(J=0, 1,…
The cross section of the process $e^+e^-\to\pi^+\pi^-$ has been measured in the center of mass energy range from 0.32 to 1.2 GeV with the CMD-3 detector at the electron-positron collider VEPP-2000. The measurement is based on a full dataset…
Following HERA experiments our interest is focused, in the present paper, on charmonium production in lepton-proton collisions. Inelastic J/\psi electroproduction is quite difficult to be measured due to the low rates of events; almost all…
To test the color-octet model of heavy quarkonium productions, we propose $\psi '$-productions at small-$p_T$ regions in polarized $pp$ collisions for the forthcoming RHIC polarized experiments, whose experimental test at $\sqrt s=50$ GeV…
The exclusive production of vector mesons in deep inelastic scattering is a hard scattering process with the well controlled size of quark configurations which dominate the production amplitude. This allows an unambiguous prediction of…
We briefly review the existing psi(2S) data taken at RHIC, the Tevatron and the LHC. We systematically compare them with colour-singlet-model predictions as a function of the center-of-mass energy, of the quarkonium rapidity and of the…
First results of the study of the process e+e- \to 4\pi by the CMD-2 collaboration at VEPP-2M are presented for the energy range 1.05--1.38 GeV. Using an integrated luminosity of 5.8 pb^{-1}, energy dependence of the processes e+e- \to…
A thorough study reveals that the only key parameter for $\psi$ ($J/\psi$, $\psi'$) polarization is the ratio $\langle O^\psi(^3S_1^{[8]})\rangle/\langle O^\psi(^3P_0^{[8]})\rangle$, if the velocity scaling rule holds. The fit of the yield…
We have calculated the cross section of $\psi'$ photoproduction at small-$p_{T}$ regions in polarized $\gamma p$ collisions for testing the color-octet model, which is based on NRQCD factorization formalism. We show that the measurement of…
The process e+e- to K+K-J/psi is observed for the first time via initial state radiation. The cross section of e+e- to K+K-J/psi for center-of-mass energies between threshold and 6.0 GeV is measured using 673 fb^{-1} of data collected with…
The Born cross section of the process $e^+e^-\to\eta J/\psi$ at a center-of-mass energy $\sqrt{s}=3.773 ~\mathrm{GeV}$ is measured to be ($8.89\pm0.88\pm0.42$)$~\mathrm{pb}$, using a data sample collected with the BESIII detector operating…
We calculate the lowest order hadronic cross sections for producing colored heavy quark-antiquark pairs in $L=S=0$ and $L=S=1$ configurations. Such $Q\Qbar[{}^1S_0^{(8)}]$ and $Q\Qbar[{}^3P_J^{(8)}]$ states hadronize into $\psi_\Q$…