Speaker
Description
The RAA of pions in small system collisions like p/d/He+Au at high pT show suppression in central collisions and enhancement in peripheral collisions. Although the suppression can be understood by probable formation of Quark Gluon Plasma (QGP) in central collision, there is no known physics mechanism to understand the observed enhancement.
As direct photons are transparent to the QGP and thus travel unaffected through them, its RAA at high pT will be unity in all centrality classes. Any deviation from this will shed light on the observed centrality dependent trend in RAA of Pi0s and thus could help us detangle true final state effects on these collisions.
In this talk, we show that the centrality binned RAA of direct photons show similar trends of suppression and enhancement as RAA of Pi0s for all centralities except the events with the highest multiplicity. This indicates that the centrality determination is biased affecting both Pi0s and direct photons. We also show a new way to define the RAA of Pi0s using the RAA of direct photons, thus removing any dependence on the Glauber Model. By this new definition, we note that there appears to be supresion in events with high multiplicity, which indicates final state effect on the Pi0 production.
| Preferred track | Jets & QCD at High Scales |
|---|---|
| Subfield | Nuclear experiment |
| Attending in-person? | Yes |
| On behalf of collaboration? | PHENIX Collaboration |
