Speaker
Description
In recent years data from small collision systems at LHC and RHIC have revealed evidence for collective behavior of the produced hadrons, and indications that a hot strongly-coupled system is being formed in these collisions. If so, the matter formed must also radiate thermal or low momentum direct photons. The versatility of RHIC puts PHENIX in an ideal position to search for any indications for thermal photon emission from recent large data sets collected with high multiplicity triggers in p+p, p+A, d+A and 3He+Au collisions at 200 GeV center-of-mass energy. In this talk we will present new measurements of direct photons from p+p and p+Au collisions reaching down to 1 GeV/c. We find that in high multiplicity p+Au events we observe a factor of 2-3 enhancement of direct photons below 4 GeV/c compared to p+p collisions, consistent with thermal photon emission. The status of the measurements in d+Au will also be presented.
