Direct Photon Production in p+p and d+Au Collisions Measured with the PHENIX Experiment

TL;DR

This paper reports measurements of direct photon production in proton-proton and deuteron-gold collisions at 200 GeV, comparing results with pQCD predictions and finding no significant cold matter effects.

Contribution

First measurement of inclusive and isolated direct photon cross-sections in p+p and d+Au collisions at 200 GeV with the PHENIX experiment, providing data for testing pQCD.

Findings

Inclusive and isolated direct photon cross-sections measured in p+p collisions.

Isolated photon contribution slightly below but consistent with pQCD predictions.

No significant cold matter effects observed in d+Au collisions.

Abstract

Direct photon yield measured in p+p and d+Au collisions at \sqrt{s} = 200 GeV with the PHENIX experiment is presented and compared to pQCD predictions. In the case of p+p collisions both the inclusive and isolated direct photon production cross-sections are measured. Relative contribution of isolated direct photons is somewhat below but still agree within errors with pQCD predictions. In the case of d+Au collisions no modifications due to presence of cold matter are found within errors.