Khachatryan, V.Işıldak, Bora2016-08-042016-08-042015-07-031079-7114http://hdl.handle.net/10679/4375https://doi.org/10.1103/PhysRevLett.115.012301Due to copyright restrictions, the access to the full text of this article is only available via subscription.The second-order azimuthal anisotropy Fourier harmonics, v2, are obtained in p−Pb and PbPb collisions over a wide pseudorapidity (η) range based on correlations among six or more charged particles. The p-Pb data, corresponding to an integrated luminosity of 35  nb−1, were collected during the 2013 LHC p-Pb run at a nucleon-nucleon center-of-mass energy of 5.02  TeV by the CMS experiment. A sample of semiperipheral PbPb collision data at sNN−−−√=2.76  TeV, corresponding to an integrated luminosity of 2.5  μb−1 and covering a similar range of particle multiplicities as the p−Pb data, is also analyzed for comparison. The six- and eight-particle cumulant and the Lee-Yang zeros methods are used to extract the v2 coefficients, extending previous studies of two- and four-particle correlations. For both the p−Pb and PbPb systems, the v2 values obtained with correlations among more than four particles are consistent with previously published four-particle results. These data support the interpretation of a collective origin for the previously observed long-range (large Δη) correlations in both systems. The ratios of v2 values corresponding to correlations including different numbers of particles are compared to theoretical predictions that assume a hydrodynamic behavior of a p−Pb system dominated by fluctuations in the positions of participant nucleons. These results provide new insights into the multiparticle dynamics of collision systems with a very small overlapping region.engrestrictedAccessarticle115100035703050000310.1103/PhysRevLett.115.012301Lee-yang zerosAngular-correlationsNuclear collisionsAnisotropic flowPpb collisionsProton-protonLong-rangeTeVEccentricitiesMultiplicity