Effect of global momentum conservation on longitudinal flow decorrelation

TL;DR

This paper investigates how global momentum conservation influences the longitudinal flow decorrelation in heavy-ion collisions, showing it weakens decorrelation and varies with collision energy, aligning with experimental data.

Contribution

It introduces the effect of global momentum conservation on longitudinal flow decorrelation and predicts its energy-dependent impact, offering new insights into heavy-ion collision dynamics.

Findings

GMC weakens longitudinal flow decorrelation.

The effect varies with collision energy, more prominent at RHIC.

Results align with experimental measurements.

Abstract

We calculate the longitudinal flow decorrelation coefficients, i.e., $r_n(\eta,\eta_r)$ for $n=2,3$, in the presence of hydro-like flow and the global momentum conservation (GMC) constraint. The longitudinal flow decorrelation is weakened due to the GMC constraint. The GMC effect is sensitive to the total number of particles involved in GMC, the average longitudinal momentum, the transverse momentum, and the reference pseudorapidity. Our results of the $r_2(\eta,\eta_{rA})/r_2(\eta,\eta_{rB})$ ratio between two reference pseudorapidity bins are consistent with the experimental measurements. We predict that the modification effect of GMC on longitudinal flow decorrelation is more noticeable at BNL Relativistic Heavy Ion Collider energies than at CERN Large Hadron Collider energies. Our finding provides a new perspective for understanding the longitudinal flow decorrelation in relativistic heavy-ion collisions.