https://doi.org/10.1140/epjc/s10052-020-7928-4
Regular Article - Theoretical Physics
Background evaluations for the chiral magnetic effect with normalized correlators using a multiphase transport model
1
Key Laboratory of Nuclear Physics and Ion-beam Application (MOE), and Institute of Modern Physics, Fudan University, Shanghai, 200433, People’s Republic of China
2
Department of Physics and Astronomy, University of California, Los Angeles, California, 90095, USA
* e-mail: subikash@fudan.edu.cn
** e-mail: gwang@physics.ucla.edu
Received:
21
January
2020
Accepted:
15
April
2020
Published online:
8
May
2020
The chiral magnetic effect (CME) induces an electric charge separation in a chiral medium along the magnetic field that is mostly produced by spectator protons in heavy-ion collisions. The experimental searches for the CME, based on the charge-dependent angular correlations (
), however, have remained inconclusive, because the non-CME background contributions are not well understood. Experimentally, the correlators have been measured with respect to the second-order (
) and the third-order (
) symmetry planes, defined as 
and 
, respectively. The expectation was that with a proper normalization, would provide a data-driven estimate for the background contributions in . In this work, we calculate different harmonics of the correlators using a charge-conserving version of a multiphase transport (AMPT) model to examine the validity of the said assumption. We find that the pure-background AMPT simulations do not yield an equality in the normalized and , quantified by 
and 
, respectively. Furthermore, we test another correlator, 
, within AMPT, and discuss the relation between different correlators.
© The Author(s), 2020
