Isolation of flow and nonflow correlations by two- and four-particle cumulant measurements of azimuthal harmonics in √s[subscript NN] = 200 GeV Au+Au collisions

• Main Authors: Stevens, Justin (Contributor), van Nieuwenhuizen, Gerrit Jan (Contributor)
• Other Authors: Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor)
• Format: Article
• Language: English
• Published: Elsevier, 2015-05-26T19:04:59Z.
• Subjects: Article
• Online Access: Get fulltext

A data-driven method was applied to Au+Au collisions a t√s[subscript NN] = 200 GeV made with the STAR detector at RHIC to isolate pseudorapidity distance Δη-dependent and Δη-independent correlations by using two- and four-particle azimuthal cumulant measurements. We identified a Δη-independent component of the correlation, which is dominated by anisotropic flow and flow fluctuations. It was also found to be independent of η within the measured range of pseudorapidity |η| < 1. In 20-30% central Au+Au collisions, the relative flow fluctuation was found to be 34% ± 2%(stat.) ± 3%(sys.) for particles with transverse momentum [subscript pT] less than 2 GeV/c. The Δη-dependent part, attributed to nonflow correlations, is found to be 5% ± 2%(sys.) relative to the flow of the measured second harmonic cumulant at |Δη| > 0.7.
Brookhaven National Laboratory
United States. Dept. of Energy. Office of Nuclear Physics
United States. Dept. of Energy. Office of High Energy Physics
National Science Foundation (U.S.)