Direct-Photon Puzzle

Goldbox (Physikalisches Institut (Heidelberg University))


Physikalisches Institut (Heidelberg University)

Im Neuenheim Feld 226 69120 Heidelberg Germany
Ana Maria Marin Garcia (GSI, Darmstadt) , Johanna Stachel (Universitaet Heidelberg) , Klaus Reygers (University of Heidelberg)

EMMI Rapid Reaction Task Force (RRTF)

Direct-Photon Puzzle

Participation in the RRTF is by invitation only. By participating everybody accepts the EMMI Code of conduct. 

The introductory symposium on Monday is an open meeting.

The goal of the RRTF is to bring together experimental and theoretical experts on the field of direct photon production in ultra-relativistic heavy-ion collisions to resolve the direct-photon puzzle. Since the first RRTF on this topic in 2014, final results on spectra and azimuthal anisotropy have been published in Au-Au at RHIC (PHENIX and STAR) and in Pb--Pb at the LHC (ALICE).  Direct photons results on small systems also became available. During this meeting we aim at quantifying the statistical significance of the puzzle, work on identifying improvements of existing analysis methods as well as novel approaches. Work will also be devoted to resolving the PHENIX/STAR discrepancy.
Moreover, state-of-the-art theoretical ideas on photon production, what can be learnt from photon HBT correlations, as well as from measurements at very low pT with a possible ALICE successor experiment will be discussed.




  • Ana Maria Marin Garcia
  • Axel Drees
  • Charles Gale
  • Chun Shen
  • Daiki Sekihata
  • Dibyendu Bala
  • Gabor David
  • Guy Moore
  • Hannah Elfner
  • Henner Büsching
  • Jean-Francois Paquet
  • Johanna Stachel
  • Klaus Reygers
  • Marvin Hemmer
  • Meike Danisch
  • Olaf Kaczmarek
  • Oscar Garcia-Montero
  • Peter Braun-Munzinger
  • Ralf Rapp
  • Roli Esha
  • Rupa Chatterjee
  • Stephan Stiefelmaier
  • Ulrich Heinz
  • Yuri Sinyukov
  • Monday, 24 July
    • 14:00 23:00
      EMMI RRTF Open Symposium GoldenBox (Physikalisches Institut)


      Physikalisches Institut