Revisit the chiral magnetic effect expectation in isobaric collisions at the relativistic heavy ion collider

• Published in: Physics letters. B Vol. 820; no. C; p. 136549
• Main Authors: Feng, Yicheng, Lin, Yufu, Zhao, Jie, Wang, Fuqiang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-09-2021; Elsevier
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/j.physletb.2021.136549

Isobaric 4496Ru+4496Ru and 4096Zr+4096Zr collisions at ▪ GeV have been conducted at the Relativistic Heavy Ion Collider to circumvent the large flow-induced background in searching for the chiral magnetic effect (cme), predicted by the topological feature of quantum chromodynamics (QCD). Considering that the background in isobar collisions is approximately twice that in Au+Au collisions (due to the smaller multiplicity) and the cme signal is approximately half (due to the weaker magnetic field), we caution that the cme may not be detectable with the collected isobar data statistics, within ∼2σ significance, if the axial charge per entropy density (n5/s) and the QCD vacuum transition probability are system independent. This expectation is generally verified by the Anomalous-Viscous Fluid Dynamics (avfd) model. While our estimate provides an approximate “experimental” baseline, theoretical uncertainties on the cme remain large.