Related papers: J/psi Spin Asymmetries in the Colour-Octet Model
The cross section of \chi_{cJ} hadroproduction is calculated in the k_t-factorization approach. We find a significant contribution of the \chi_{c1} state due to non-applicability of the Landau-Yang theorem because of off-shell gluons. The…
A single-spin asymmetry in the distribution of exclusively produced pi^+ mesons azimuthally around the virtual photon direction relative to the lepton scattering plane has been measured for the first time in deep-inelastic scattering of…
Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons from transversely polarized protons at the HERMES experiment. The asymmetries were studied as a function of the azimuthal angle $\psi$ about…
We analyze the dependence of CP-odd asymmetries on longitudinally polarized e+ and e- beams in neutralino production and subsequent leptonic two-body decays. We give numerical examples of the asymmetries and of the cross sections in the…
We consider J/psi meson photoproduction on protons at high energies at the leading order in alpha_s using conventional parton model and k_t-factorization approach of QCD. It is shown that in the both cases the colour singlet mechanism gives…
The leading and sub-leading order results for pion electroproduction in polarized and unpolarized semi-inclusive deep-inelastic scattering, are considered putting emphasis on transverse momentum dependent effects appearing in azimuthal…
Using substantially larger data samples collected by the CLEO III detector, we report on new measurements of the decays of Upsilon(1S) to charmonium final states, including J/Psi, psi(2S), and chi_cJ. The latter two are first observations…
Based on a prior model on double pion photoproduction on the proton, successfully tested in total cross sections and invariant mass distributions, we make a theoretical study of the angular dependence of helicity asymmetries from the…
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…
Data and their interpretations are reviewed for $J/\psi$ and $\psi^{\prime}$ production in heavy ion collisions with particular emphasis on the recently reported discontinuity in $Pb$-$Pb$ reactions. The experimental set-up is described and…
It is shown that the existence of left-right asymmetry in single-spin inclusive Lambda production, together with the characteristic features of the data, should be considered as another clear signature for the existence of orbiting valence…
We compute \frac{d\sigma}{dp_T} of the J/\psi production in pp collisions at RHIC at \sqrt s = 500 and 200 GeV by using both the color octet and singlet models in the framework of non-relativistic QCD. The J/\psi we compute here includes…
We proceed for the first time to the evaluation of the Born cross section for J/psi+eta(c) production, namely via g+g -> J/psi+eta(c)+g, and show that it has a harder P_T spectrum than the J/psi-pair yield at Born level. If one stuck to a…
We show that the production of J/psi or Upsilon pairs in unpolarised pp collisions is currently the best process to measure the momentum-distribution of linearly-polarised gluons inside unpolarised protons through the study of azimuthal…
We consider J/psi photoproduction in e+ e- as well as linear photon colliders. We find that the process is dominated by the resolved photon channel. Both the once-resolved and twice-resolved cross-sections are sensitive to (different…
We investigate the inclusive production of double quarkonia ($J/\psi$, $\psi(2S)$, $\Upsilon$ mesons) in polarized hadron-hadron collisions, considering the kinematic configuration where the transverse momentum of each pair of bound states…
Working in the nonrelativistic-QCD factorization framework at next-to-leading order in $\alpha_s$, we fit the relevant color octet (CO) long-distance matrix elements (LDMEs) of the $\psi(2S)$ meson, $\langle {\cal…
It is demonstrated that measurements of the spin asymmetry for di-jet production at future polarized colliders appear to be particularly suited for a first determination of the so far unmeasured parton densities of circularly polarized…
The motion of charmonium in heavy ion collisions is described by a three dimensional transport equation with initial production and continuous regeneration in hot medium. The observation of apparently stronger $J/\psi$ suppression at…
The $J/\psi$ and $\psi(2S)$ charmonium states, composed of $c\bar{c}$ quark pairs and known since the 1970s, are widely believed to serve as ideal probes to test quantum chromodynamics in high-energy hadronic interactions. However, there is…