With the advent of the RHIC II and LHC programs, our field is entering a new discovery phase – it is therefore timely to take note of where we are with respect to our current state of knowledge of QCD matter and what the greatest theoretical challenges will be for the next few years.
In order to capture a representative cross section of opinions, we have asked a number of leading scientists in our field to identify the 3-5 most important challenges which the field of hot and dense QCD matter theory has to address. We will post their responses in the order in which they are received.
- What is the high energy limit of QCD and is it controlled by new forms of matter? What are the forms of such matter and their properties?
- What is the phase structure of matter at finite temperature and density? Are there true phase transitions in QCD, or only rapid cross overs? How does such matter manifest itself in nature and in collisions of high energy strongly interacting particles?
- How and to what degree does matter thermalize in high energy hadronic collisions? Are there novel mechanisms for thermalization?
- What is the nature of glue? How does it affect confinement and chiral symmetry restoration? How does the spectra of strongly interacting particles arise? Is this possible to understand not only in large scale computations but with analytical methods?