Direct-photon measurements in p+p and Au+Au collisions at \sqrt {sNN} = 200 GeV from the PHENIX experiment are presented. The p+p results are found to be in good agreement with next-to-leading-order (NLO) perturbative QCD calculations. Direct-photon yields in Au+Au collisions scale with the number of inelastic nucleon--nucleon collisions and do not exhibit the strong suppression observed for charged hadrons and neutral pions. This observation is consistent with models which attribute the suppression of high-pT hadrons to energy loss of quarks and gluons in the hot and dense medium produced in Au+Au collisions at RHIC.
PACS numbers: 13.85.Qk, 25.75.Dw
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