Longitudinal decorrelation measures of flow magnitude and event-plane angles in ultra-relativistic nuclear collisions

Understand

We discuss the forward-backward correlations of harmonic flow in Pb+Pb collisions at the CERN Large Hadron Collider (LHC), applying standard multibin measures, as well as proposed here new measures.

• We illustrate the methods with hydrodynamic model simulations based on event-by-event initial conditions from the wounded quark model with asymmetric rapidity emission profiles.
• Within the model we examine independently the event-plane angle and the flow magnitude decorrelations.
• We find specific hierarchy between various flow decorrelation measures and confirm certain factorization relations.