Charge-dependent anisotropy Fourier coefficients ($v_n$) of particle azimuthal distributions are measured in $p\mathrm{Pb}$ and $\mathrm{PbPb}$ collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=5.02\mathrm{TeV}$ with the CMS detector at the LHC. The normalized difference in the second-order anisotropy coefficients ($v_2$) between positively and negatively charged particles is found to depend linearly on the observed event charge asymmetry with comparable slopes for both $p\mathrm{Pb}$ and $\mathrm{PbPb}$ collisions over a wide range of charged particle multiplicity. In $\mathrm{PbPb}$, the third-order anisotropy coefficient $v_3$ shows a similar linear dependence with the same slope as seen for $v_2$. The observed similarities between the $v_2$ slopes for $p\mathrm{Pb}$ and $\mathrm{PbPb}$, as well as the similar slopes for $v_2$ and $v_3$ in $\mathrm{PbPb}$, are compatible with expectations based on local charge conservation in the decay of clusters or resonances, and constitute a challenge to the hypothesis that, at LHC energies, the observed charge asymmetry dependence of $v_2$ in heavy ion collisions arises from a chiral magnetic wave.

• Received 29 August 2017
• Revised 12 October 2018

DOI:https://doi.org/10.1103/PhysRevC.100.064908

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

©2019 CERN, for the CMS Collaboration