Azimuthally-sensitive femtoscopy from RHIC to LHC in hydrodynamics with statistical hadronization

TL;DR

This paper uses hydrodynamics and statistical hadronization to successfully model azimuthally-sensitive femtoscopy in heavy-ion collisions at RHIC and LHC, predicting femtoscopic observable behaviors and emission patterns.

Contribution

It demonstrates that a hydrodynamic model with statistical hadronization can accurately reproduce azimuthally-sensitive femtoscopic observables at RHIC and makes predictions for LHC energies.

Findings

Reproduces azimuthal variation of HBT radii at RHIC

Predicts moderate growth of HBT radii at LHC

Shows complex space-time emission patterns

Abstract

Azimuthally-sensitive femtoscopy for heavy-ion collisions at RHIC and LHC is explored within the approach consisting of the hydrodynamics of perfect fluid followed by statistical hadronization. It is found that for the RHIC initial conditions the very same framework that reproduces the standard soft observables (including the transverse-momentum spectra, the elliptic flow, and the azimuthally-averaged HBT radii) leads to a proper description of the azimuthally-sensitive femtoscopic observables - we find that the azimuthal variation of the side and out HBT radii is very well reproduced for all centralities, while the out-side correlation is somewhat too large for non-central events. Concerning the dependence of the femtoscopic parameters on kT we find that it is very well reproduced for the out and side radii, and fairly well for the long radius. The model is then extrapolated for the LHC energy. We predict the overall moderate growth of the HBT radii and the decrease of their azimuthal oscillations. Such effects are naturally caused by longer evolution times. In addition, we discuss in detail the space-time patterns of particle emission. We show that they are quite complex and argue that the overall shape seen by the femtoscopic methods cannot be easily disentangled on the basis of simple-minded arguments.