Probing the chiral magnetic wave in pPb and PbPb collisions at √SNN = 5.02 TeV using charge-dependent azimuthal anisotropies

Charge-dependent anisotropy Fourier coefficients (v$_{n}$) of particle azimuthal distributions are measured in pPb and PbPb collisions at $\sqrt{^{s}_{NN}}$ =5.02TeV 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 pPb and PbPb collisions over a wide range of charged particle multiplicity. In 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 pPb and PbPb, as well as the similar slopes for v$_{2}$ and v$_{3}$ in 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.