Systematic study of high pT hadron production in small collision systems by the PHENIX experiment at RHIC

Abstract

High pT hadrons in the small systems of d/3He+Au and p+Al/Au collisions have been measured at the midrapidity (|ƞ| < 0.35) as well as at the forward and backward rapidities (1.2 < |ƞ| < 2.4) at √sNN =200 GeV. A clear system and centrality ordering in the Rp/d/HeA was observed for midrapidity π0 production. Hadron Rcp as a function of rapidity in forward and backward regions show an opposite trend to what HIJING++ predicted. Together with the difference of Rcp in p+Al/Au collisions, the observation can be understood consistently with the measured long-range two-particle correlations, hinting the possible medium creation similar to A+A collisions.