Charged Hadron Production in Cu + Au Collisions at 200 GeV in the PHENIX Experiment

Abstract

Hadronization of quark–gluon plasma is one of the most discussed problems in modern high-energy physics. It has been found in the PHENIX experiment (2002) that the ratio of (anti)proton yields to ${{\pi }^{ \pm }}$-meson yields in Au + Au collisions at the energy of 130 GeV (and later at 200 GeV) is anomalously large as compared to proton–proton collisions. The only model capable of explaining this anomaly is one of the hadronization models based on parton recombination. Measurements of ${{\pi }^{ \pm }},~{{K}^{ \pm }}$, and ${{\left( {p + \bar {p}} \right)} \mathord{\left/ {\vphantom {{\left( {p + \bar {p}} \right)} 2}} \right. \kern-0em} 2}$ in asymmetric Cu + Au collisions at the energy of 200 GeV are reported, which have been performed to study the effect of collision geometry on production of charged hadrons.