Charge asymmetry dependency of π⁺/ π⁻elliptic flow in Au + Au collisions at = 200 GeV

Abstract

In this proceedings, we present STAR's measurement of v 2 difference between positively charged pions and negatively charged pions at low transverse momentum for Au + Au collisions at √ s N N = 200 GeV. The integrated v 2 of π + (π − ), 0.15 < p T < 0.5 GeV/c, decreases (increases) linearly with the increasing charge asymmetry A ± . The v 2 difference between π + and π − is proportional to A ± and the slope parameters have their order of magnitude of about 0.01. All of these observed features are consistent with the predication based on Chiral Magnetic Wave. The centrality dependence of the v 2 difference is different than that was predicted.

Chiral separation and chiral magnetic effects in a slab: The role of boundaries

“…This phenomenon is known in the literature as the chiral magnetic effect (CME) and its origin is related to the famous chiral anomaly 7 . Moreover, the charge-dependent correlations and flow, observed in heavy-ions collisions at RHIC [23][24][25][26][27] and LHC 28 , appear to be in a qualitative agreement with the predictions of the CME 29,30 (for recent reviews, see also Refs. [31][32][33] ).…”

Anomalous transport effects and possible environmental symmetry ‘violation’ in heavy-ion collisions

“…More recently the STAR collaboration has also systematically measured this v 2 difference as a function of net charge asymmetry at high collision energy [89,103], which shows a linear dependence on A ± just as predicted in (23) …”

Electromagnetic fields and anomalous transports in heavy-ion collisions—a pedagogical review

“…Recently, the v 2 splitting of charged pions was measured by STAR Collaboration [215,245,246] and the data is in agreement with the CMW predictions in several aspects (See Fig. 18 for the experimental result for the centrality dependence of the slope parameter r at √ s = 200 GeV): quadrupole similar with that produced by CMW (Note that this electric-field induced effect exists even at A ch = 0) [7,79], the electromagnetic chirality E · B distributes in the transverse plane like a chiral dipole which when combined with triangle anomaly and CME can also induce a charge quadrupole [79], the mean-field potential from the hadronic as well as partonic phases acts differ- Figures are from Ref.…”