Electromagnetic Probes of Hot and Dense Matter


                      ECT* Programme, Trento, June 3-11, 2005


    Organizers: Peter Braun-Munzinger, Charles Gale and Ralf Rapp (coordinator)

     Scope of the Meeting:  

      Due to their penetrating character, electromagnetic (e.m.) observables (photons and lepton pairs) are unique and
      powerful probes of the high-energy density matter created in high-energy collisions of heavy nuclei.
      On the one hand, photons and dileptons of invariant masses and/or transverse momenta above about 1 GeV are  
      believed to reveal the temperatures achieved in the highly excited nuclear systems, and thus, in turn, test the degree
      of thermalization in the early phases of the reaction. On the other hand, low-mass dileptons directly probe possible  
      in-medium modifications of the light vector mesons (rho, omega and phi), and therefore allow to address the question
      of hadronic mass generation in connection with the restoration of chiral symmetry in the QCD phase transition(s).       
      The above issues have been intensively studied theoretically, stimulated by tantalizing experimental results obtained
      by the first generation of experiments during the 1990's. At the BEVALAC and the SPS substantial excess radiation
      over expected sources has been observed at masses and transverse momenta from 0 to 3GeV.  However, as of now,
      the theoretical interpretations remain inconclusive.  The enhancement below the free rho-mass is equally well described
      by a broadening or (and) a reduced mass of the vector spectral functions, whereas thermal radiation at higher mass  
      could not be unambiguously discerned from primordial sources (i.e. open-charm decays and nuclear modifications of
      perturbative QCD processes).  This situation is expected to dramatically improve owing to a considerable influx of
      new experimental results by the time of the meeting, including data at SIS energies from HADES, at SPS energies
      from CERES and NA60, as well as at RHIC energies from PHENIX and STAR.
      This workshop is intended to gather about 40 of the world-leading experimental and theoretical experts to perform
      an in-depth exchange, analysis and discussion of, and make progress in, our understanding of electromagnetic probes
      of hot and dense nuclear matter.
       Topics include:       

     Workshop Information: