Effects of non-uniform acceptance in anisotropic flow measurement

TL;DR

This paper discusses how to accurately measure anisotropic flow in detectors with non-uniform azimuthal acceptance by introducing new observables and a self-consistent correction method based on experimental data.

Contribution

It introduces a novel set of observables and a correction technique that explicitly accounts for non-uniform detector acceptance in anisotropic flow measurements.

Findings

The proposed observables provide independent measures of flow.

The method allows direct determination of acceptance corrections from data.

Practical summary of the correction technique is provided.

Abstract

Applicability of anisotropic flow measurement techniques and their extension for detectors with non-uniform azimuthal acceptance are discussed. Considering anisotropic flow measurement with two and three (mixed harmonic) azimuthal correlations we introduce a set of observables based on the x and y components of the event flow vector. These observables provide independent measures of anisotropic flow, and can be used to test self-consistency of the analysis. Based on these observables we propose a technique that explicitly takes into account the effects of non-uniform detector acceptance. Within this approach the acceptance corrections, as well as parameters which define the method applicability, can be determined directly from experimental data. For practical purposes a brief summary of the method is provided at the end.