Speaker
Description
As a colorless probe, direct photons balance the $p_T$ of the away-side jet at
leading order. Direct photon-hadron correlations are thus an excellent probe for
nuclear structure and QCD effects, including parton energy loss in the
Quark-Gluon Plasma.
PHENIX has measured $\pi^0$ and direct photon-triggered two-particle azimuthal
correlations in a variety of collision systems ranging from p+p to Au+Au at 200
GeV. In p+Au and d+Au collisions, no modification of the per-trigger jet yield or
away-side correlation width compared to p+p collisions is observed for direct
photon triggered correlations while an increase in the away-side width for
$\pi^0$ triggered correlations in p+Au has been measured. In Au+Au and Cu+Au collisions, direct photons have been identified statistically as well as using an isolation cut. Combining data sets from different collision systems allows us to quantify the transition from suppression at high
$z_T$ ($p_{T,h}/p_{T,gamma}$) to the enhancement of low $z_T$ particles relative to p+p, and to study this transition as a function of trigger $p_T$. The implication for our understanding of cold and hot nuclear matter from these measurements will be discussed.
| Content type | Experiment |
|---|---|
| Collaboration | PHENIX |
| Centralised submission by Collaboration | Presenter name already specified |
