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

• Published in: Physics letters. B 2015-05, Vol.745 (C), p.40-47
• Main Authors: Abdelwahab, N.M., Adamczyk, L., Adkins, J.K., Agakishiev, G., Aggarwal, M.M., Ahammed, Z., Alekseev, I., Alford, J., Anson, C.D., Aparin, A., Arkhipkin, D., Aschenauer, E.C., Averichev, G.S., Banerjee, A., Beavis, D.R., Bellwied, R., Bhasin, A., Bhati, A.K., Bhattarai, P., Bielcik, J., Bielcikova, J., Bland, L.C., Bordyuzhin, I.G., Borowski, W., Bouchet, J., Brandin, A.V., Brovko, S.G., Bültmann, S., Bunzarov, I., Burton, T.P., Butterworth, J., Caines, H., Calderón de la Barca Sánchez, M., Campbell, J.M., Cebra, D., Cendejas, R., Cervantes, M.C., Chaloupka, P., Chang, Z., Chattopadhyay, S., Chen, H.F., Chen, J.H., Chen, L., Cheng, J., Cherney, M., Chikanian, A., Christie, W., Codrington, M.J.M., Contin, G., Cramer, J.G., Crawford, H.J., Cui, X., Das, S., Davila Leyva, A., De Silva, L.C., Debbe, R.R., Dedovich, T.G., Deng, J., Derevschikov, A.A., Derradi de Souza, R., di Ruzza, B., Didenko, L., Dilks, C., Ding, F., Djawotho, P., Dong, X., Drachenberg, J.L., Draper, J.E., Du, C.M., Dunkelberger, L.E., Dunlop, J.C., Efimov, L.G., Engelage, J., Engle, K.S., Eppley, G., Eun, L., Evdokimov, O., Eyser, O., Fatemi, R., Fazio, S., Fedorisin, J., Filip, P., Fisyak, Y., Flores, C.E., Gagliardi, C.A., Gangadharan, D.R., Garand, D., Geurts, F., Gibson, A., Girard, M., Gliske, S., Greiner, L., Grosnick, D., Gunarathne, D.S., Guo, Y., Gupta, A., Gupta, S., Guryn, W., Haag, B., Hamed, A.
• Format: Article
• Language: English
• Subjects: flow; heavy-ion; non-flow; NUCLEAR PHYSICS AND RADIATION PHYSICS; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Relativistic Heavy Ion Collider
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/j.physletb.2015.04.033

A data-driven method was applied to Au+Au collisions at √sNN = 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 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. (author)