Detailed HBT measurements with respect to the event plane and collision energy in Au+Au collisions at PHENIX

TL;DR

This paper presents azimuthal HBT measurements relative to second and third order event planes in Au+Au collisions at 200 GeV, revealing source shape and evolution details, and compares results across different energies.

Contribution

It provides new azimuthal HBT measurements relative to higher order event planes in Au+Au collisions at RHIC, exploring initial fluctuation effects at freeze-out.

Findings

HBT radii show azimuthal dependence relative to higher order event planes.

Comparison of HBT results at different energies reveals energy dependence of source shape.

Results suggest persistence of initial fluctuation effects at freeze-out.

Abstract

The azimuthal dependence of 3D HBT radii relative to the event plane gives us information about the source shape at freeze-out. It also provides information on the system's evolution by comparing it to the initial source shape. In recent studies, higher harmonic event planes and flow have been measured at RHIC and the LHC, which result primarily from spatial fluctuations of the initial density across the collision area. If the shape caused by initial fluctuations still exists at freeze-out, the HBT measurement relative to higher order event plane may show these features. We present recent results of azimuthal HBT measurements relative to $2^{nd}$- and $3^{rd}$-order event planes in Au+Au 200 GeV collisions with the PHENIX experiment. Recent HBT measurements at lower energies will be also shown and compared with the 200 GeV result.