Identified particle production, azimuthal anisotropy, and interferometry measurements in Au+Au collisions at sqrt(s)NN = 9.2 GeV

Abstract

We present the first measurements of identified hadron production, azimuthal anisotropy, and pion interferometry from Au+Au collisions below the nominal injection energy at the BNL Relativistic Heavy-Ion Collider (RHIC) facility. The data were collected using the large acceptance solenoidal tracker at RHIC (STAR) detector at √sNN=9.2 GeV from a test run of the collider in the year 2008. Midrapidity results on multiplicity density dN/dy in rapidity y, average transverse momentum 〈pT〉, particle ratios, elliptic flow, and Hanbury-Brown–Twiss (HBT) radii are consistent with the corresponding results at similar √sNN from fixed-target experiments. Directed flow measurements are presented for both midrapidity and forward-rapidity regions. Furthermore the collision centrality dependence of identified particle dN/dy, 〈pT〉, and particle ratios are discussed. These results also demonstrate that the capabilities of the STAR detector, although optimized for √sNN=200 GeV, are suitable for the proposed QCD critical-point search and exploration of the QCD phase diagram at RHIC