Measurements of soft and intermediate p(T) photons from hot and dense matter at RHIC-PHENIX

作者：Yamaguchi Yorito^*

来源：Nuclear Physics A, 2009, 830(1-4): 575C-578C.

DOI：10.1016/j.nuclphysa.2009.10.107

The measurements of direct photons in 1.0 < pT < 5.0 GeV/c for p+p and Au+Au collisions have been made through the virtual photon method at PHENIX. The fraction of the direct y* component to the inclusive e(+)e(-) yield is determined by a shape analysis using the e(+)e(-) mass spectra in m(ee) < 300 MeV/c(2) for 1.0 < pT < 5.0 GeV/c. The real direct photon spectra in p+p and Au+Au collisions are obtained from the virtual direct photon fractions, and a significant excess over a binary-scaled p+p result is seen in Au+Au collisions. Hydrodynamical models which reproduce the Au+Au result indicate the initial temperature of the matter is higher than the critical temperature of QGP. The d+Au data taken in 2008 are promising to evaluate the contribution of the nuclear effects due to its large statistics.

• 出版日期2009-11-1