A previously constructed transport approach to calculate the evolution of quarkonium yields and spectra in heavy-ion collisions is applied to Pb-Pb ( √ s = 2.76 A TeV) collisions at the Large Hadron Collider (LHC). In this approach spectral properties of charmonia are constrained by Euclidean correlators from thermal lattice QCD and subsequently implemented into a Boltzmann equation accounting for both suppression and regeneration reactions. Based on a fair description of SPS and RHIC data, we provide predictions for the centrality dependence of J/ψ yields at LHC. The main uncertainty is associated with the input charm cross section, in particular its hitherto unknown reduction due to shadowing in nuclear collisions. Incomplete charm-quark thermalization and non-equilibrium in charmonium chemistry entail a marked reduction of the regeneration yield compared to the statistical equilibrium limit.

We study the heavy quarkonium within the basis light-front quantization approach. We implement the one-gluon exchange interaction and a confining potential inspired by light-front holography. We adopt the holographic light-front wavefunction (LFWF) as our basis function and solve the non-perturbative dynamics by diagonalizing the Hamiltonian matrix. We obtain the mass spectrum for charmonium and bottomonium. With the obtained LFWFs, we also compute the decay constants and the charge form factors for selected eigenstates. The results are compared with the experimental measurements and with other established methods.including the electron anomalous magnetic moment [16,17], non-linear Compton scattering [18,19] and the positronium spectrum [20,21]. In this paper, we apply the BLFQ approach to the heavy quarkonium.Working with the full QCD Hamiltonian is a formidable task. In practice, we truncate the Fock space to a finite number of particles. The leading-order truncation |qq + |qqg introduces the one-gluon exchange which produces correct short-distance physics as well as the spin-dependent interaction needed for the fine and hyperfine structures. The Abelian version of this interaction was extensively used in the literature [20,[22][23][24][25] to calculate the QED bound-state spectrum in LFD. However, the one-gluon exchange itself is not sufficient to reproduce the hadron spectrum since confinement is also needed. Holographic QCD provides an appealing approximation to confinement.

We set up a framework in which in-medium charmonium properties are constrained by thermal lattice quantum chromodynamics and subsequently implemented into a thermal rate equation enabling the comparison with experimental data in heavy-ion collisions. Specifically, we evaluate phenomenological consequences for charmonium production originating from two different scenarios in which either the free or the internal energy are identified with the in-medium two-body potential between charm and anticharm quarks. These two scenarios represent J /ψ "melting temperatures" of approximately 1.25T c ("weak binding") and 2T c ("strong binding"), respectively. Within current uncertainties in dissociation rates and charm-quark momentum spectra, both scenarios can reproduce the centrality dependence of inclusive J /ψ yields in nuclear collisions at the Super Proton Synchrotron (SPS) and the Relativistic Heavy-Ion Collider (RHIC) reasonably well. However, the "strong-binding" scenario associated with the internal energy as the potential tends to better reproduce current data on transverse momentum spectra at both SPS and RHIC.

We study the production of bottomonium states in heavy-ion reactions at collider energies available at RHIC and LHC. We employ an earlier constructed rate equation approach which accounts for both suppression and regeneration mechanisms in the quark-gluon plasma (QGP) and hadronization phases of the evolving thermal medium. Our previous predictions utilizing two limiting cases of strong and weak bottomonium binding in the QGP are updated by (i) checking the compatibility of the pertinent spectral functions with lattice-QCD results for euclidean correlators, (ii) adapting the initial conditions of the rate equation by updating bottom-related input cross sections and the charged-particle multiplicity of the fireball, and (iii) converting our calculations into observables as recently measured by the STAR and CMS experiments. Our main findings are a preference for strong Υ binding as well as a significant regeneration component at the LHC.