Flow fluctuations in Pb plus Pb collisions at root s(NN)=5.02 TeV with the ATLAS detector
Measurements of four-particle cumulants c(n)4 for n = 1, 2, 3, 4 are presented using 470 mu b(-1) of Pb+Pb collisions at root s(NN) = 5.02 TeV with the ATLAS detector at the LHC. These cumulants provide information on the event-by-event fluctuations of single harmonics p(v(n)). For the first time, a negative c(1)4 is observed. The c(4)4 is found to be negative in central collisions but changes sign around 20-25% centrality. This behavior is consistent with a nonlinear contribution to v(4) that is proportional to v(2)(2).