Measurement of $\pi^{0}$ and $\gamma$ in d+Au collisions at $\sqrt{s_{NN}}=$ 200 GeV by PHENIX experiment

TL;DR

This paper reports precise measurements of neutral pions and photons in d+Au collisions at 200 GeV to investigate initial state effects in heavy nuclei, improving upon previous data with higher luminosity.

Contribution

It provides more accurate high $p_T$ measurements of $b0$ and $b3$ in d+Au collisions, testing initial state modifications with improved data quality.

Findings

Enhanced precision in high $p_T$ $b0$ and $b3$ measurements

Results consistent with no initial state modification within errors

Supports the hypothesis that high $p_T$ suppression in Au+Au is a final state effect.

Abstract

Previous results indicated that high $p_T$ particle suppression in Au+Au interactions is a final state effect, since R$_{dA}$ ratios were compatible with unity, albeit within large experimental errors. It is important to test this conclusion to higher precision since the modification of structure functions may be involved. Recent d+Au data taken in 2008 improve the integrated luminosity by about a factor of thirty compared to the 2003 data. A more precise measurement of both $\pi^0$ and $\gamma$ at higher $p_T$ will shed new light on whether the initial state in the heavy nuclei is modified.