Isolation of Flow and Nonflow by Two- and Multi-Particle Cumulant Measurements of image in image Au + Au Collisions by STAR

We apply a data-driven method to STAR Au + Au collisions at image to isolate Δη-dependent and Δη-independent correlations by using two- and four-particle Q-cumulant image measurements. The Δη-independent part, dominated by flow, is found to be η-independent within the STAR TPC of ±1 unit of pseudo-rapidity. The Δη-dependent part may be associated to nonflow, and is responsible for the Δη drop in the measured two-particle image cumulant. We combine our result to four- and six-particle cumulants to gain further insights on the nature of flow fluctuations.