Direct photons in 200 GeV p+p, d+Au, and Au+Au from PHENIX

TL;DR

This paper reports measurements of direct photons in proton-proton, deuteron-gold, and gold-gold collisions at 200 GeV using the PHENIX experiment, including a novel method for low transverse momentum detection via internal conversion.

Contribution

It introduces a new measurement technique for low p_T direct photons through internal conversion in heavy-ion collisions.

Findings

First measurement of direct photons in these collision systems at 200 GeV

Successful detection of low p_T photons via internal conversion

Provides data for understanding photon production in high-energy nuclear collisions

Abstract

Direct photons were measured with the PHENIX experiment in p+p, d+Au, and Au+Au at sqrt(s_NN) = 200 GeV. To tackle the p_T region below 5 GeV/c, direct photons were measured through their internal conversion into e^+e^- in Au+Au collisions.