Direct virtual photon and dielectron production in Au+Au collisions at $ \sqrt{s_{NN}} $ = 200 GeV at STAR

May 19, 2014, 2:40 PM
helium (darmstadtium)



Schlossgraben 1 64283 Darmstadt Germany
Contributed Talk Electromagnetic Probes Electromagnetic probes


Chi Yang (USTC/BNL)


One important physics goal of ultra-relativistic heavy-ion collisions is to study the fundamental properties of a hot, dense medium created in these collisions. This medium is expected to emit thermal radiation which is in the form of direct photons and dileptons. Once produced, photons and leptons traverse the strongly interacting medium with minimal interactions. The fully installed Time-of-Flight Detector in 2010 enables clean electron identification from low to intermediate transverse momentum ($p_{T}$). In this talk, we will present the direct virtual photon production for 1<$p_{T}$<5 GeV/$c$ derived from the dielectron continuum in the dielectron invariant mass region 0.1<$M_{ee}$<0.3 GeV/$c^{2}$ from one billion $\sqrt{s_{NN}}$ = 200 GeV Au+Au minimum bias events taken in 2010 and 2011. In addition, we will present the centrality and $p_{T}$ dependence of dielectron production and the dielectron azimuthal angle correlation in the intermediate mass(1.1<$M_{ee}$<3 GeV/$c^{2}$) region in this dataset. The relevant results from $\sqrt{s}$ = 200 GeV p+p collisions taken in 2012 will also be discussed. Comparisons to model calculations including hadronic and partonic thermal radiation will be made for both the direct virtual photon and dielectron production in Au+Au collisions.
On behalf of collaboration: STAR

Primary author

Chi Yang (USTC/BNL)

Presentation materials