Identified particle production, azimuthal anisotropy, and interferometry measurements in Au+Au collisions at $\sqrt{s_{NN}}$ = 9.2 GeV

TL;DR

This paper reports the first measurements of identified hadron production, azimuthal anisotropy, and interferometry in Au+Au collisions at 9.2 GeV, demonstrating STAR's capability to explore the QCD phase diagram and critical point.

Contribution

It provides the initial data on particle production and flow at 9.2 GeV, supporting the search for the QCD critical point and phase transition at RHIC.

Findings

Results are consistent with fixed target experiments at similar energies.

Directed flow measurements at mid and forward rapidity are presented.

Data demonstrate STAR's readiness for QCD critical point search.

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 Relativistic Heavy-Ion Collider (RHIC) facility. The data were collected using the large acceptance STAR detector at $\sqrt{s_{NN}}$ = 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 HBT radii are consistent with the corresponding results at similar $\sqrt{s_{NN}}$ 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 the readiness of the STAR detector to undertake the proposed QCD critical point search and the exploration of the QCD phase diagram at RHIC.