Transverse hydrodynamics and the early-thermalization problem at RHIC

TL;DR

This paper proposes a hybrid hydrodynamic model combining transverse-hydrodynamics and perfect-fluid hydrodynamics to address the early-thermalization problem in RHIC heavy-ion collisions, successfully describing soft hadronic observables.

Contribution

It introduces a hybrid model with Landau matching to connect different hydrodynamic regimes, offering a potential solution to early thermalization issues at RHIC.

Findings

Successful description of soft hadronic observables

Circumvents the early-thermalization problem

Addresses the HBT puzzle

Abstract

The problem of early thermalization of matter produced in relativistic heavy-ion collisions at RHIC is discussed in the framework of a hybrid model that consists of the transverse-hydrodynamics stage followed by the standard perfect-fluid hydrodynamics stage and freeze-out. The two hydrodynamic regimes are connected with the help of Landau matching conditions. A satisfactory description of the soft hadronic observables is achieved. This indicates that the early-thermalization problem and also the HBT puzzle may be to large extent circumvented.