Electromagnetic Probes in PHENIX

Abstract

Electromagnetic probes are arguably the most universal tools to study the different physics processes in high energy hadron and heavy ion collisions. In this paper we summarize recent measurements of real and virtual direct photons at central rapidity by the PHENIX experiment at RHIC in p+p, d+Au and Au+Au collisions. We also discuss the impact of the results and the constraints they put on theoretical models. At the end we report on the immediate as well as on the mid-term future of photon measurements in PHENIX.

Direct photons—basis for characterizing heavy-ion collisions

“…Theoretical studies show that a part of fragment processes arises as a leading order [1]. The source of radiations is from various processes and manifests as a function of transverse momentum (p T ) [2] (figure 1(b)). Photons with high p T are primarily produced in the initial hard scattering, and often called 'hard photons'.…”