Related papers: Direct-Photon Production in Au+Au Collisions at RH…
We analyse the recently available experimental data on direct photon productions from Au+Au collisions at $\sqrt{s_{NN}}$=200 GeV RHIC and from Pb+Pb collisions at $\sqrt{s_{NN}}$=2.76 TeV LHC energies. The transverse momentum ($p_T$)…
A brief overview of direct-photon measurements in ultra-relativistic nucleus-nucleus collisions is given. The results for Pb+Pb collisions at sqrt{s_NN} = 17.3 GeV and for Au+Au collisions at sqrt{s_NN} = 200 GeV are compared to estimates…
The measurements of direct photons in $1.0 < p_{T} < 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 virtual direct photon component to the inclusive $e^{+}e^{-}$…
Direct photons provide a insightful tool to study the different stages of a heavy ion collision, especially the formation of a quark-gluon plasma, without being influenced by the strong interaction and hadronization processes. The yield of…
The PHENIX collaboration presents first measurements of low-momentum ($0.4<p_T<3$ GeV/$c$) direct-photon yields from Au$+$Au collisions at $\sqrt{s_{_{NN}}}$=39 and 62.4 GeV. For both beam energies the direct-photon yields are substantially…
The first measurement of direct photons in Au+Au collisions at sqrt(s_NN) = 200 GeV is presented. The direct photon signal is extracted as a function of the Au+Au collision centrality and compared to NLO pQCD calculations. The direct photon…
Recent results on direct photons and dileptons from the PHENIX experiment opened up a possibility of landscaping electro-magnetic radiation over various kinetic energies in heavy ion collisions. Results on direct photon measurement in Au+Au…
We present direct photon-hadron correlations in 200 GeV/A Au$+$Au, $d$$+$Au and $p$$+$$p$ collisions, for direct photon $p_T$ from 5--12 GeV/$c$, collected by the PHENIX Collaboration in the years from 2006 to 2011. We observe no…
Photons are emitted at all stages of relativistic heavy-ion collisions and do not interact with the medium strongly. With access to the versatility of RHIC, measurements of low momentum direct photons are made possible across different…
Direct photons are a powerful tool to study the hot and dense matter created in heavy-ion collisions at RHIC, since they are created in the different stages of the collision. Since they do not interact via the strong force, they can travel…
Recent results from the PHENIX experiment at RHIC are presented. In this second part of the overview we discuss new results on direct photon production at low p_T in Au+Au collisions and a systematic study of J/psi production in various…
A theoretical derivation of photon bremsstrahlung, induced by the interactions of an energetic quark in a hot and dense quark-gluon plasma, is given in the framework of the reaction operator approach. For the physically relevant case of…
Direct photon production in minimum bias d+Cu and d+Au and central Cu+Cu and Au+Au collisions at center of mass energies $\sqrt{s}=62.4$ GeV and 200GeV at RHIC is systematically investigated. We study the jet quenching effect, the…
Since the earliest days of Heavy Ion Physics thermal soft photon radiation emitted during the reaction had been theorized as a smoking gun signal for formation of a quark-gluon plasma and as a tool to characterize its properties. In recent…
PHENIX has measured the e^+e^- pair continuum in sqrt(s_NN)=200 GeV Au+Au and p+p collisions over a wide range of mass and transverse momenta. The e^+e^- yield is compared to the expectations from hadronic sources, based on PHENIX…
Results from the PHENIX experiment at RHIC in p-p and Au+Au collisions are reviewed from the perspective of measurements in p-p collisions at the CERN-ISR which serve as a basis for many of the techniques used. Issues such as J/Psi…
Prompt photons produced in a hard reaction are not accompanied with any final state interaction, either energy loss or absorption. Therefore, besides the Cronin enhancement at medium transverse momenta pT and small isotopic corrections at…
The direct photon spectrum measured by the PHENIX collaboration in Au + Au collisions at sqrt{s_{NN}}=200 GeV has been analyzed. It has been shown that the data can be reproduced reasonably well by assuming a deconfined state of thermalized…
We report the measurement of direct photons at midrapidity in Au+Au collisions at sqrt{s_NN} = 200 GeV. The direct photon signal was extracted for the transverse-momentum range of 4 GeV/c < p_T < 22 GeV/c, using a statistical method to…
Comparing dilepton data from Au+Au to p+p collisions at RHIC energies PHENIX revealed two striking features: (i) a large excess of the dilepton yield at low mass and low pT in central Au+Au and (ii) a significant enhancement of direct real…