Splitting of elliptic flow in a tilted fireball

TL;DR

This paper investigates how the splitting of elliptic flow in different momentum regions can reveal information about the initial angular momentum and rapidity distribution in relativistic heavy ion collisions using hydrodynamic models.

Contribution

It introduces a hydrodynamic approach to analyze elliptic flow splitting, linking it to initial state angular momentum and rapidity distribution, providing a new method to constrain initial conditions.

Findings

Elliptic flow splitting is mainly driven by directed and triangular flows.

The study connects flow splitting to initial angular momentum and rapidity distribution.

Hydrodynamic models can effectively describe the observed flow phenomena.

Abstract

The splitting of elliptic flow measured in different regions of the momentum space of produced hadrons has been recently studied in transport models and proposed as a sensitive probe of the angular momentum carried by the fireball produced in a relativistic heavy ion collision. The initial state angular momentum also gives rise to rapidity odd directed flow which has been measured. We consider a relativistic hydrodynamic framework with the initial matter distribution suitably calibrated to describe the observed directed flow and apply it to study the spilt in the elliptic flow. Our study suggests that the split in the elliptic flow is mostly driven by directed and triangular flows and may be used to constrain models of initial state rapidity distribution of matter in the fireball.