Elliptic flow from two- and four-particle correlations in Au+Au collisions at root s(NN)=130 GeV

0185730 - UJF-V 20033031 RIV US eng J - Journal Article
Adler, C. - Ahammed, Z. - Allgower, C. - Amonett, J. - Anderson, B. D. - Anderson, M. - Šumbera, Michal - Zborovský, Imrich
Elliptic flow from two- and four-particle correlations in Au+Au collisions at root s(NN)=130 GeV.
Physical Review. C. Roč. 66, č. 3 (2002), s. 034904. ISSN 0556-2813
R&D Projects: GA MŠMT ME 475
Institutional research plan: CEZ:AV0Z1048901
Keywords : heavy-ion collisions * phase-transition
Subject RIV: BF - Elementary Particles and High Energy Physics
Impact factor: 2.848, year: 2002

Elliptic flow holds much promise for studying the early-time thermalization attained in ultrarelativistic nuclear collisions. Flow measurements also provide a means of distinguishing between hydrodynamic models and calculations which approach the low density (dilute gas) limit. Among the effects that can complicate the interpretation of elliptic flow measurements are azimuthal correlations that are unrelated to the reaction plane (nonflow correlations). Using data for Au + Au collisions at roots(NN)=130 GeV from the STAR time projection chamber, it is found that four-particle correlation analyses can reliably separate flow and nonflow correlation signals. The latter account for on average about 15% of the observed second-harmonic azimuthal correlation, with the largest relative contribution for the most peripheral and the most central collisions. The results are also corrected for the effect of flow variations within centrality bins. This effect is negligible for all but the most central bin, where the correction to the elliptic flow is about a factor of 2. A simple new method for two-particle flow analysis based on scalar products is described. An analysis based on the distribution of the magnitude of the flow vector is also described.
Permanent Link: http://hdl.handle.net/11104/0082113