Possibility to disentangle anisotropic flow, flow fluctuation, and nonflow assuming Gaussian fluctuations

Abstract

We suggest the possibility to disentangle anisotropic flow, flow fluctuation, and nonflow using two-, four-, and six-particle azimuthal moments assuming Gaussian fluctuations. We show that such disentanglement is possible when the flow fluctuations are large, comparable to the average flow magnitude. When fluctuations are small, the disentanglement becomes difficult. We verify our results with a toy-model Monte Carlo simulation.

Comments: 6 pages, 1 table, 1 figure. Shortened introduction, removed appendices with technical details, added a reference to S Voloshin's earlier study on the subject, and several other changes to improve the discussions. Clarified the role of harmonic planes and definite positivity in experimental "flow" measurements, published version