Related papers: The color-singlet contribution to e^+ e^- ->J/psi …
The direct production rate of $\psi$ in the $\Upsilon$ decay is shown to be dominated by the process $ \Upsilon \to ggg^*$ followed by $g^* \to \psi$ via the color-octet mechanism proposed recently to explain the anomalous prompt charmonium…
$J/\psi$ production cross section considering the contributions of both color-singlet and color-octet $c\bar c$ channels is calculated. The result is used to study the suppression of $J/\psi$ in nuclear collisions. With absorption cross…
The prompt $J/\psi$ photoproduction within the non-relativistic QCD (NRQCD) framework at the future Circular Electron Positron Collider (CEPC) is studied, including the contributions from both direct and resolved photons. Employing…
We study J/psi production in pp collisions at sqrt(s)=1.96 and 7 TeV using the Colour-Singlet Model (CSM), including next-to-leading order (NLO) corrections and dominant alphaS^5 contributions (NNLO*). We find that the CSM reproduces the…
The question how well nonrelativistic QCD (NRQCD) factorization can describe quarkonium production has been subject to debate since its invention. We review our recent reanalysis of a classic next-to-leading order color octet (CO) long…
We calculate the transverse single-spin asymmetry (SSA) for $J/\psi$ production in proton-proton collisions, within non-relativistic QCD, employing the transverse momentum dependent, generalized parton model, which includes both spin and…
We discuss the prompt production of $J/\psi$ mesons in proton-proton collisions at the LHC within a NRQCD $k_{t}$-factorization approach using Kimber-Martin-Ryskin (KMR) unintegrated gluon distributions (UGDF). We include both direct…
We investigate the $J/\psi$ + c + $\bar{c}$ photoproduction in $e^+ e^-$ collision at the LEP II energy. The physical motivations for this study are: 1) such next-to-leading order(NLO) process was not considered in previous investigations…
The associated production of a J/psi and a photon in photon-hadron collisions is considered, and shown to be a good probe of the presence of colour-octet mediated channels in quarkonia production, as predicted by the factorization approach…
We revisit inclusive J/psi and Upsilon photoproduction at lepton-hadron colliders, namely in the limit when the exchanged photon is quasi real. Our computation includes the next-to-leading-order (NLO) alpha_s corrections to the…
We investigate threshold resummation effects in the production of a color sextet (antitriplet) scalar at next-to-next-to-leading logarithmic (NNLL) order at the LHC in the frame of soft-collinear effective theory. We show the total cross…
For $J/\psi$ pair production at hadron colliders, we present the full next-to-leading order (NLO) calculations with the color-singlet channel in nonrelativistic QCD. We find that the NLO result can reasonably well describe the LHCb measured…
We calculate cross sections and transverse momentum distributions for the incoherent diffractive production of vector mesons $J/\psi$ and $\Upsilon$ on heavy nuclei. In distinction to coherent diffraction, the nucleus is allowed to break…
Presented here is a calculation of inelastic $J/\psi$ production in polarized photon-hadron collisions under the framework of NRQCD factorization formalism. We consider the photoproduction of $\jpsi$ in the energy range relevant to HERA.…
One of the most challenging open problems in heavy quarkonium physics is the double charm production in $e^+e^-$ annihilation at B factories. The measured cross section of $e^+ e^- \to J/\psi + \eta_c$ is much larger than leading order (LO)…
The production of J/Psi mesons in photon photon collisions allows for a test of factorization in color-octet processes as predicted by NRQCD and observed at the Tevatron. We calculate the cross sections for J/Psi production with direct and…
We study the $\eta_c$ photoproduction in $ep$ collisions in this paper. The short-distance coefficients for $c\bar{c}(^1S_0^{[1]})$, $c\bar{c}(^1S_0^{[8]})$, $c\bar{c}(^3S_1^{[8]})$, and $c\bar{c}(^1P_1^{[8]})$ photoproductions are…
In this paper, we present a detailed next-to-leading-order (NLO) study of $J/\psi$ angular distributions in $e^{+}e^{-} \to J/\psi+\eta_c,\chi_{cJ}$ ($J=0,1,2$) within the nonrelativistic QCD factorization (NRQCD). The numerical NLO…
We calculate the direct production rate of $J/\psi$ in top quark decays. The color-octet $J/\psi$ production via $t\rightarrow W^+ b J/\psi$ is shown to have a large branching ratio of order $1.5\times 10^{-4}$, which is over an order of…
There is serious disagreement between the predictions of Non-Relativistic Quantum Chromodynamics (NRQCD) and the data on $J/\psi$ polarisation which has persisted for almost a quarter of a century. We find that if we account for the effect…