Heavy ion collisions - seen via hard probes and jets

by Thorsten Renk (University of Jyväskylä)

Wednesday 25 Mar 2009, 15:30 → 16:45 Europe/Stockholm

122:026

Quantum Chromodynamics (QCD) is usually applied in the limit of large momentum transfer where it becomes perturbatively calculable. However, the theory can also be studied in a collective limit where it describes matter at high tempratures and densities and exhibits a phase transition from confined hadrons as relevant degrees of freedom to deconfined partons. These properties can be studied experimentally in ultrarelativistic heavy-ion collisions, and a strong experimental program is currently being carried out at the Brookhaven RHIC and will also be joined by efforts at the CERN LHC. In the first part of my talk, I review some of the important concepts of the present understanding of QCD matter at high temerpatures and densities, in particular the description in terms of a near-ideal liquid. In the second part of the talk, I show how perturbatively calculable hard processes taking place in the collision can be used to probe important properties of the bulk fluid matter and review the current state of the art in describing the medium modifications of single hadron spectra, back-to-back correlations and jets.