Event-plane correlators

TL;DR

This paper introduces a new, less detector-demanding method for analyzing event-plane correlators in heavy-ion collisions, enabling better comparison between theory and experiment, and provides both validation and new predictions.

Contribution

The paper presents a novel analysis procedure for event-plane correlators that improves upon previous methods in terms of detector acceptance and allows for unambiguous theory-data comparison.

Findings

The new method yields results in excellent agreement with ATLAS data.

Previous hydrodynamic models only achieved qualitative agreement.

Predictions for new four-plane correlators are provided.

Abstract

Correlators between event planes of different harmonics in relativistic heavy-ion collisions have the potential to provide crucial information on the initial state of the matter formed in these collisions. We present a new procedure for analyzing such correlators, which is less demanding in terms of detector acceptance than the one used recently by the ATLAS collaboration to measure various two-plane and three-plane correlators in Pb-Pb collisions at LHC. It can also be used unambiguously for quantitative comparison between theory and data. We use this procedure to carry out realistic simulations within the transport model AMPT. Our theoretical results are in excellent agreement with the ATLAS data, in contrast with previous hydrodynamic calculations which only achieved qualitative agreement. We present predictions for new correlators, in particular four-plane correlators, which can easily be analyzed with our new method.