High-pT pi0, eta, Identified and Inclusive Charged Hadron Spectra from PHENIX

TL;DR

This paper reports extended measurements of high-pT pi0, eta, and charged hadron spectra in various collision systems, revealing suppression patterns and ratios consistent with jet fragmentation and energy loss models.

Contribution

It provides new high-pT spectra measurements in Cu+Cu collisions and compares suppression and particle ratios across systems, testing models of energy loss and universal scaling.

Findings

Strong suppression observed in central Au+Au and Cu+Cu collisions.

RAA becomes independent of pT above 5 GeV/c across systems.

Particle ratios are consistent with normal jet fragmentation.

Abstract

PHENIX has extended the measurement of the pi0, eta, identified and inclusive charged hadron up to 20 GeV/c, and extended the measurement to the Cu+Cu collision system. A strong suppression is observed for both pi0 and charged hadron yields in central Au+Au and Cu+Cu collisions. Comparing Au+Au and Cu+Cu systems, RAA becomes independent of pT above 5 GeV/c. Its centrality dependence is compared with two models in order to test for universal Npart scaling that is independent of system; results are inconclusive. The results are compatible with energy loss predictions. In addition, the ratio of eta to pi0 approaches, within uncertainties, a constant value of 0.4-0.5 at high pT in p+p, d+Au, and Au+Au, while the ratio of Ks to pi0 is also consistent with a constant value at high pT in d+Au and p+p. These results are compatible with normal jet fragmentation.