Di-electron Continuum at PHENIX

Abstract

The PHENIX experiment at RHIC has been carried out to investigate the properties of QGP. Di-electron yields in p+p and Au+Au collisions have been measured. An enhancement of the yield over a hadronic cocktail calculation is clearly seen for $p_T<1.0$GeV/$c$ and $150<m_{ee}<750$MeV/$c^2$ in Au+Au collisions, while the result in p+p collisions is consistent with the calculation. The fraction of the virtual direct photon component to the di-electron yield is measured from a shape analysis using the di-electron mass distributions for $1.0<p_T<5.0$GeV/$c$ and $m_{ee}<300$MeV/$c^2$, and the real direct photon spectra are deduced from the fractions obtained for p+p and Au+Au collisions. An excess of the direct photon yield above a binary-scaled p+p result is seen in Au+Au collisions. The excess is fitted with an exponential function with an inverse slope parameter of $221\pm 23\pm 18$MeV.

4 pages, 4 figures. Invited talk at the XLIIIth Rencontres de Moriond (QCD and High Energy Interactions), La Thuile, Vallee d'Aoste, Italy, Mar. 8-15, 2008

References in corpus (4)

• Enhanced production of direct photons in Au+Au collisions at sqrt(s_NN)=200 GeV and implications for the initial temperature
• Dilepton mass spectra in p+p collisions at sqrt(s)= 200 GeV and the contribution from open charm
• Enhancement of the dielectron continuum in sqrt{s_NN} = 200 GeV Au+Au collisions
• e+e- Pairs: a clock and a thermometer of heavy ion collisions