Recent progress in anisotropic hydrodynamics

TL;DR

This paper reviews recent advances in anisotropic hydrodynamics, a framework that better models the early-time pressure anisotropy in quark-gluon plasma by incorporating momentum-space anisotropies at leading order, improving the description of rapidly expanding systems.

Contribution

It introduces recent progress in anisotropic hydrodynamics and presents preliminary phenomenological predictions for particle spectra and elliptic flow.

Findings

Anisotropic hydrodynamics more accurately describes early-time plasma dynamics.

Preliminary predictions align with experimental observations.

Framework improves modeling of pressure anisotropies in quark-gluon plasma.

Abstract

The quark-gluon plasma created in a relativistic heavy-ion collisions possesses a sizable pressure anisotropy in the local rest frame at very early times after the initial nuclear impact and this anisotropy only slowly relaxes as the system evolves. In a kinetic theory picture, this translates into the existence of sizable momentum-space anisotropies in the underlying partonic distribution functions, <p_L^2> << <p_T^2>. In such cases, it is better to reorganize the hydrodynamical expansion by taking into account momentum-space anisotropies at leading-order in the expansion instead of as a perturbative correction to an isotropic distribution. The resulting anisotropic hydrodynamics framework has been shown to more accurately describe the dynamics of rapidly expanding systems such as the quark-gluon plasma. In this proceedings contribution, I review the basic ideas of anisotropic hydrodynamics, recent progress, and present a few preliminary phenomenological predictions for identified particle spectra and elliptic flow.