▪ Abstract We present an overview of the scientific opportunities that would be offered by a high-energy electron-ion collider. We discuss the relevant physics of polarized and unpolarized electron-proton collisions and of electron-nucleus collisions. We also describe the current accelerator and detector plans for a future electron-ion collider. This review is dedicated to the memory of Professor Vernon W. Hughes.

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Study of the fundamental structure of matter with an electron-ion collider

We present the results from the heavy quarks and quarkonia working group. This report gives benchmark heavy quark and quarkonium cross sections for $pp$ and $pA$ collisions at the LHC against which the $AA$ rates can be compared in the study of the quark-gluon plasma. We also provide an assessment of the theoretical uncertainties in these benchmarks. We then discuss some of the cold matter effects on quarkonia production, including nuclear absorption, scattering by produced hadrons, and energy loss in the medium. Hot matter effects that could reduce the observed quarkonium rates such as color screening and thermal activation are then discussed. Possible quarkonium enhancement through coalescence of uncorrelated heavy quarks and antiquarks is also described. Finally, we discuss the capabilities of the LHC detectors to measure heavy quarks and quarkonia as well as the Monte Carlo generators used in the data analysis.

Hard probes in heavy ion collisions at the LHC: heavy flavour physics

We discuss the nuclear dependence of psi and psi' production in hadron-nucleus interactions as a function of longitudinal momentum fraction x{sub F}. Nuclear effects such as final-state absorption, interactions with comovers, shadowing of parton distributions, energy loss, and intrinsic heavy-quark components are described separately and incorporated into the model which is then compared to the preliminary E866 data. The resulting nuclear dependence of Drell-Yan production at 800 GeV and proposed measurements of psi, psi' and Drell-Yan production at 120 GeV are also calculated.

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Xf dependence of psi and Drell-Yan production

Energy dependence of J/ψ production in Au+Au collisions at sNN=39,62.4 and 200GeV

At high energies the saturation effects associated to the high parton density should modify the behavior of the observables in proton-nucleus and nucleus-nucleus scattering. In this paper we investigate the saturation effects in the nuclear $J/\Psi$
 production and estimate the modifications in the energy dependence of the cross section as well as in the length of the nuclear medium. In particular, we calculate the ratio of $J/\Psi$
 to Drell-Yan cross sections and show that it is strongly modified if the high density effects are included. Moreover, our results are compared with the data from the NA50 Collaboration and predictions for the RHIC and LHC kinematic regions are presented. We predict an additional $J/\Psi$
 suppression associated to the high density effects.

C. Lee

Papers

Nuclear effects on heavy quark production results from Fermilab experiments E772 and E789