Related papers: Colour Octet effects in Quarkonium Physics
We include two loop, relativistic one loop and second order relativistic tree level corrections, plus leading nonperturbative contributions, to obtain a calculation of the lower states in the heavy quarkonium spectrum correct up to, and…
We report the recent progress in the studies of D-wave heavy quarkonia production from gluon fragmentation at the Tevatron and in Z^0 decays, and the D-wave charmonia production in B decays. We show that the color-octet contributions are 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…
In this contribution, we present the unquenched quark model as an extension of the constituent quark model that includes the effects of sea quarks via a $^{3}P_{0}$ quark-antiquark pair-creation mechanism. Particular attention is paid to…
We consider the contributions of both color-singlet and octet $c\bar c$ bound states for studying the suppression of $J/\psi$ production in quark gluon plasma (QGP) and have found that the existence of the color-octet $c\bar c$ may cause…
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…
More than 30 years after the discovery of the J/psi, its production mechanism is still poorly understood. With the LHC data it will be possible to study quarkonia up to very high transverse momenta and with high statistics. In this note we…
In this paper, the color-octet long distance matrix elements are studied though the inclusive $J/\psi$ production in $e^{+}e^{-}$ annihilation within the non-relativistic QCD frame. The calculations are up-to next-to-leading order with the…
Inclusive S- and P-wave charmonium productions in the bottomonium ground state $\eta_b$ decay are calculated at the leading order in the strong coupling constant $\alpha_s$ and quarkonium internal relative velocity $v$ in the framework of…
Production mechanisms for quarkonium states in hadronic collisions remain difficult to understand. The decay angular distributions of J/$\psi$ or $\Upsilon(nS)$ states into $\mu^+ \mu^-$ final states are sensitive to the matrix elements in…
Inclusive $\chi_{cJ}$ $(J=0,1,2)$ production from $\Upsilon(1S)$ decay is studied within the framework of nonrelativistic QCD (NRQCD) factorization at leading order in $v_Q^2$, which includes the contributions of $b\bar{b}({}^3S_1^{[1]})\to…
We investigate the inclusive production of double quarkonia ($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…
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 present some preliminary results on the next-to-leading order calculation in QCD of quarkonium production cross sections in hadronic collisions. We will show that the NLO total cross sections for $P$-wave states produced at high energy…
Recent observations of the spectrum of J/psi produced in e+ e- collisions at the Upsilon(4S) resonance are in conflict with fixed-order calculations using the Non-Relativistic QCD (NRQCD) effective field theory. One problem is that leading…
The $J/\psi+Z^0$ associated production at the LHC is an important process in investigating the color-octet mechanism of non-relativistic QCD in describing the processes involving heavy quarkonium. We calculate the next-to-leading order…
Inclusive production of $\Upsilon J/\psi$ pair in proton-proton interation at LHCb is considered. This process is forbidden at leading order of perturbation theory, so such channels as double parton scattering, $\chi_b\chi_c$ pair…
We compute the third-order corrections to the heavy quarkonium spectrum and production/annihilation rates due to the leading renormalization group running of the static potential. The previously known complete ${\cal O}(m_q\alpha_s^5)$…
We study the diffractive photo- and leptoproductions of $J / \psi$ and $\psi '$ on the proton, and examine the validity of the small-size color dipole approximation to the production of radially excited heavy quarkonium. The dipole model…
We present a discussion of radiative decays $\chi_{cJ}\rightarrow\gamma \rho (\omega, \phi)$. The decay amplitudes are computed within the QCD factorisation framework. NRQCD has been used in the heavy meson sector as well as a collinear…