Session C12: Invited Session: Hard Hadronic Probes of Nuclear Collisions

Interpreting jet results from RHIC and LHC

Measurements of fully reconstructed jets, which are collimated bunches of high momentum hadrons, have become available at the LHC and RHIC and will be much improved with planned updates at RHIC. Jets can be understood as an experimental signature of high energy partons that were produced early in the collision. Comparing jet observables in central heavy-ion collisions to proton-proton collisions can tell us about the medium produced in heavy-ion collisions and the interactions of high energy partons with the medium. I present Monte-Carlo computations of jet observables in heavy-ion collisions at RHIC and LHC that are based on perturbative QCD interactions of high energy partons with a strongly coupled hydrodynamic medium. Monte-Carlo techniques allow for the most direct link of theoretical calculations to experimental observables. For example, jet reconstruction can be performed in exactly the same way. I compare the same set of jet observables at RHIC and LHC, looking for potential differences in the relevant physical processes at different collision energies.   

Quarkonium production in heavy-ion collisions

I will review the recent quarkonium measurements at the LHC in PbPb collisions at 2.76 TeV, and compare to the lower energy measurements as well as to the theoretical background.   

Recent Finite Temperature Lattice Results

Hard scattering processes provide in-medium probes of the quark-gluon plasma (QGP) created in heavy-ion collision experiments. Their sensitivity to the properties of the medium is an experimental and theoretical tool for studying the evolution of QGP. Lattice QCD is a non-perturbative field-theoretical framework that allows one to study (equilibrium) aspects of the hot medium from first principles. The physics of hard probes that can be addressed on the lattice includes heavy quarkonia, screening of heavy quarks, spectral functions and heavy quark diffusion. I review recent progress in Lattice QCD related to these phenomena and to some extent the advances in our general understanding of the thermodynamics of QCD.