Effect of flow fluctuations and nonflow on elliptic flow methods

Understand

We discuss how the different estimates of elliptic flow are influenced by flow fluctuations and nonflow effects.

• It is explained why the event-plane method yields estimates between the two-particle correlation methods and the multiparticle correlation methods.
• It is argued that nonflow effects and fluctuations cannot be disentangled without other assumptions.
• However, we provide equations where, with reasonable assumptions about fluctuations and nonflow, all measured values of elliptic flow converge to a unique mean v_{2,PP} elliptic flow in the participant plane and, with a Gaussian assumption on eccentricity fluctuations, can be converted to the mean v_{2,RP} in the reaction plane.