1210.6640 (Li Yi et al.)

Isolation of Flow and Nonflow by Two- and Multi-Particle Cumulant
Measurements of $v_n$ in $\sqrt{s_{NN}} = 200$ GeV Au+Au Collisions by STAR    [PDF]

Li Yi, for the STAR Collaboration

We apply a data-driven method to STAR Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV to isolate $\Delta\eta$-dependent and $\Delta\eta$-independent correlations by using two- and four-particle Q-cumulant $v_{n}$ measurements. The $\Delta\eta$-independent part, dominated by flow, is found to be $\eta$-independent within the STAR TPC of $\pm1$ unit of pseudo-rapidity. The $\Delta\eta$-dependent part may be associated to nonflow, and is responsible for the $\Delta\eta$ drop in the measured two-particle $v_{2}$ cumulant. We combine our result to four- and six-particle cumulants to gain further insights on the nature of flow fluctuations.

View original: http://arxiv.org/abs/1210.6640