相关论文: Color-Octet $J/\psi$ Production in the $\Upsilon$ …

We study J/psi photoproduction via fragmentation at next-to-leading order in the QCD-improved parton model, using the nonrelativistic factorization formalism proposed by Bodwin, Braaten, and Lepage. We consider direct and resolved…

In this work, we present more detail of the calculation on the NLO QCD corrections to polarization of direct J/psi production via color singlet at Tevatron and LHC, as well as the results for Upsilon for the first time. Our results show…

We present the leading order differential and total rates for J/\psi production at LEP. By leading order we mean all terms of the form alpha_s[alpha_s log(M_Z^2/M_{psi}^2)]^n and alpha_s^{n+1} log^l(z^2) log^m(M_Z^2/M_{psi}^2), (l+m=2n-1),…

In this work, we calculate the next-to-leading-order (NLO) QCD corrections to the process $p+p \to J/\psi + \gamma$ via the color-singlet mechanism at the LHC. The results show that the partial cross section ($p_t^{J/\psi}>$3GeV and…

We show that the colour-singlet process $\Upsilon \to J/\Psi + c\bar{c}g$ significantly contributes to the inclusive process $\Upsilon \to J/\Psi + X$. We calculate the partial width and the momentum distribution of the produced $J/\Psi$ in…

Color-octet contributions to quarkonia production at LEP are studied herein. The short distance formation of heavy quark-antiquark pairs in color-octet configurations via gluon fragmentation processes is significantly enhanced relative to…

The inclusive cross section for the production of $J/\psi$ in $e^+ e^-$ annihilation is studied using a recently developed factorization formalism. In addition to the conventional color-singlet contribution, we include contributions from $c…

We calculate the rate of production of W+Upsilon and Z+Upsilon at the Tevatron. We find the cross sections at a center-of-mass energy of 1.8 TeV to be roughly 450 pb for W+Upsilon and 150 pb for Z+Upsilon. The dominant production mechanism…

We study contributions from color-octet quarkonium formation mechanisms to $p_\perp$-integrated $\psi'$ production cross sections in pion-nucleon reactions. The observed polarization of the $\psi'$ is not reproduced by the lowest-order…

We investigate the pattern of asymmetries in the colour-octet model for inclusive production of charmonium with polarised initial state hadrons and photons. We find that singly polarised asymmetries vanish. The double polarised asymmetry…

We study the $\Upsilon$ exclusive decay into double charmonium, specifically, the $S$-wave charmonium $ J/\psi$ plus the $P$-wave charmonium $\chi_{c0,1,2}$ in the NRQCD factorization framework. Three distinct decay mechanisms, i.e., the…

We analyze charmonium and bottomonium production at fixed target experiments. We find that inclusion of color octet production channels removes large discrepancies between experiment and the predictions of the color singlet model for the…

We firstly re-examine hadroproduction of prompt J/psi's at the Fermilab Tevatron finding that those colour-octet matrix elements presented in literature are systematically overestimated due to the overlooking of the effective primordial…

A factorization theorem for $P$-wave quarkonium production, recently derived by Bodwin, Braaten, Yuan and Lepage, is applied to $\Upsilon \to \chi_{cJ} + X$, where $\chi_{cJ}$ labels the ${}^3 P_J$ charmonium states. The widths for…

We revisit the $J/\psi$ pair production issue at the Fermilab Tevatron Run II with the center-of-mass energy $\sqrt{s}=1.96 \mathrm{TeV}$. Both color-singlet and -octet production mechanisms are considered. Our result shows that the…

We update the theoretical predictions for direct Y(nS) hadroproduction in the framework of NRQCD. We show that the next-to-leading order corrections in alpha_s to the color-singlet transition significantly raise the differential cross…

We investigate the direct photoproduction of $J/\psi+c\bar{c}$ at $ep$ colliders with different center of mass energies in this paper. For the color-singlet part we take into account the contribution from QED subprocess as well as the QCD…

We study $J/\psi$ and $\eta_c$ inclusive production in $\Upsilon$ decay within the framework of nonrelativistic-QCD (NRQCD) factorization. In the latter case, for which no experimental data exist so far, we also include the $h_c$ feed-down…

In this paper, we study the $J/\psi(\Upsilon)$ production in Z boson decay in color-singlet model(CSM). We calculate the next-to-leading-order (NLO) QCD correction to $Z \to Quarkonium+Q\bar{Q}$, the dominant contribution in the CSM, with…

A slow $J/\psi$ bump exists in the inclusive $B\to J/\psi + X$ spectrum, while the softness of $J/\psi$ spectrum in $\Upsilon(1S) \to J/\psi + X$ decay is in strong contrast with expectations from color octet mechanism. We propose {\it…