Longitudinal correlation of the triangular flow event plane in a hybrid approach with hadron and parton cascade initial conditions

TL;DR

This study investigates the longitudinal correlations of triangular flow event planes in heavy ion collisions using a hybrid model with different initial conditions, revealing persistent correlations and challenging assumptions about flux tubes.

Contribution

It compares hadronic and partonic initial conditions in a hybrid approach to understand longitudinal flow correlations in heavy ion collisions.

Findings

Initial state shows strong longitudinal correlation of event plane angles.

Correlation persists in final particle distributions despite dilution.

Ridge-like structures can arise from gluon radiation, not necessarily flux tubes.

Abstract

The longitudinal long-range correlations of the triangular flow event plane angles are calculated in a Boltzmann + hydrodynamics hybrid approach. The potential to disentangle different energy deposition scenarios is explored by utilizing two different transport approaches for the early non-equilibrium evolution. In the hadronic transport approach the particle production in high energy heavy ion reactions is mainly governed by string excitation and fragmentation processes which are absent in the parton cascade approach. We find that in both approaches the initial state shows a strong longitudinal correlation of the event plane angles which is diluted but still persists in the final state momentum space distributions of the produced particles. A ridge-like structure can also be caused by near-collinear gluon radiation in a parton cascade approach and does not necessarily prove longitudinal flux tubes in the initial state.