Possible observables for the chiral electric separation effect in Cu + Au collisions

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The quark-gluon plasma (QGP) generated in relativistic heavy-ion collisions could be locally parity-odd. In parity-odd QGP, the electric field may induce a chiral current which is called the chiral electric separation effect (CESE). We propose two possible observables for CESE in Cu + Au collisions: The first one is the correlation ζαᵦ= [2(ϕα+ϕβ-2Ψ RP)]; the second one is the charge-dependent event-plane angle Ψq₂ with q=± being charge. Nonzero Δζ=ζopp-ζsame and ΔΨ=|Ψ₂+-Ψ₂-| may signal the CESE in Cu + Au collisions. Within a multiphase transport model, we study how the final state interaction affects these observables. We find that the correlation γαᵦ=(ϕα+ϕβ-Ψ RP) is sensitive to the out-of-plane charge separation caused by the chiral magnetic effect and to the in-plane charge separation caused by the in-plane electric field, but it is not sensitive to the CESE. On the other hand, Δζ and ΔΨ are sensitive to the CESE. Therefore, we suggest that the future experiments measure the above observables in Cu+Au collisions in order to disentangle different chiral and charge separation mechanisms.