Estimate of a nonflow baseline for the chiral magnetic effect in isobar collisions at RHIC

Recently, STAR reported the isobar ( 44 96 Ru + Ru, 40 Zr Zr) results for chiral magnetic effect (CME) search. The Ru+Ru to Zr+Zr ratio of CME-sensitive observable Δ γ , normalized by elliptic anisotropy υ 2 ), is observed be close inverse multiplicity N ) ratio. In other words, / naive background baseline unity. However, nonflow correlations are expected cause deviate from To further understand results, we decompose contributions (isobar ratio) into three terms and quantify each term using in measurement, published data, HIJING simulation. From these studies, estimate a CME discuss its implications.