Event-plane flow analysis without non-flow effects

Understand

The event-plane method, which is widely used to analyze anisotropic flow in nucleus-nucleus collisions, is known to be biased by nonflow effects,especially at high $p_t$.

• Various methods (cumulants, Lee-Yang zeroes) have been proposed to eliminate nonflow effects, but their implementation is tedious, which has limited their application so far.
• In this paper, we show that the Lee-Yang-zeroes method can be recast in a form similar to the standard event-plane analysis.
• Nonflow correlations are strongly suppressed by using the information from the length of the flow vector, in addition to the event-plane angle.