Related papers: Issues in Quarkonium Production
We present a rigorous next-to-leading order analysis of J/psi yield and polarization within the factorization theorem of nonrelativistic QCD (NRQCD). To the orders considered, this framework depends on three free parameters, the color-octet…
Recent measurements of J/psi production in e^+ e^- colliders pose a challenge to the NRQCD factorization theorem for quarkonium production. Discrepancies between leading order calculations of color-octet contributions and the momentum…
I discuss issues related to charmonium production, in view of physics possibilities at a 15 ... 30 GeV continuous beam electron facility. High energy photo- and hadroproduction of heavy quarkonia presents several challenges to QCD models…
Cross sections of the heavy quarkonium production process $e^+e^-\to H + \gamma$ at the c.m. energy of $Z^0$-boson resonance are calculated at leading order in $\alpha_s$ with relativistic corrections resummed within the framework of…
We work out and review prospects for future quarkonium physics at HERA. We focus on the impact of color-octet contributions and discuss how measurements at HERA can be used to test the picture of quarkonium production as developed in the…
I compare current approaches to quarkonium production with regard to what they tell us about quarkonium polarization. Predictions for $J/\psi$ polarization in hadron-hadron and photon-hadron collisions are summarized.
I review the NRQCD factorization approach for quarkonium production and compare its predictions with measurements in hadron-hadron and ep collisions.
At existing and planned neutrino factories (high energy and high intensity neutrino beam facilities) precision studies of QCD in neutrino-nucleon interactions are a realistic opportunity. We investigate charmonium production in fixed target…
We present a complete calculation of the higher-order perturbative QCD corrections to inelastic photoproduction of $J/\psi$ particles. A comprehensive analysis of total cross sections and differential distributions for the energy range of…
Non-relativistic QCD (NRQCD) is used to calculate the relativistic correction to the amplitude for exclusive photoproduction of vector Quarkonia in the near-threshold region within the generalized parton distribution (GPD) framework. The…
Approximately taking into account the higher-order effects due to multiple-gluon initial-state radiation, we extract from the latest Tevatron data of prompt J/psi hadroproduction the leading colour-octet matrix elements within the…
After achieving a successful description of charmonia production in proton-proton (pp) collisions within Non-Relativistic Quantum Chromodynamics (NRQCD) and modified NRQCD (MNRQCD) frameworks, we now extend our study to proton-lead (p-Pb)…
We compare LHCb measurements of $J/\psi$ and $\psi(2S)$ transverse momentum distributions within jets with QCD calculations, which may be crucial in understanding the quarkonium production mechanism. Our theoretical calculations are based…
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…
Some examples of the most recent applications of the NRQCD factorization approach to quarkonium phenomenology are presented. In the first part of the talk the NLO calculations for $\chicj$ and $\Upsilon$ decays rates are compared to the…
The production cross sections of $h_c$ and $h_b$, the ${}^1P_1$ quarkonia can be predicted in Non-Relativistic Quantum Chromodynamics (NRQCD) using heavy quark symmetry. Our study includes predictions for both the integrated cross-section…
To clarify the outstanding problem in charmonium production that existing theories cannot explain the observed cross sections of $\chi_{cJ}$ (J=0,1,2) and ratio $R_{\chi_c}=\sigma_{\chi_{c2}}/\sigma_{\chi_{c1}}\approx 0.75$ (in contrast to…
We re-analyze Tavatron data on charmonium hadroproduction in the framework of the color-octet model implemented in the event generator PYTHIA taking into account initial-state radiation of gluons and Altarelli-Parisi evolution of…
Due to the heavy-quark symmetry of Non-Relativistic Quantum Chromodynamics (NRQCD), the cross-section for the production of $\eta_c$ can be predicted. This NRQCD prediction when confronted with data from the LHCb is seen to fail miserably.…
The NRQCD factorization approach for calculating inclusive production of heavy quarkonium gives unambiguous predictions for the polarization of quarkonium states. The factorization formula for polarized states can be obtained by using the…