Recently, the DØ Collaboration measured the CP-violating like-sign dimuon charge asymmetry in neutral B decays, finding a 3.2σ difference from the standard-model (SM) prediction. A non-SM charge asymmetry a s sl suggests a newphysics (NP) contribution to B s -B s mixing. In this case, in order to explain the measured value of a s sl within its 1σ range, NP must be present in Γ s 12 , the absorptive part of the mixing. In this paper, we examine whether such an explanation is possible in models with flavor-changing Z (ZFCNC) or Z ′ (Z ′ FCNC) gauge bosons. The models must also reproduce the measured values of the indirect CP asymmetry S ψφ in B s → J/ψφ, and ∆Γ s , the B s -B s width difference. We find that the ZFCNC model cannot reproduce the present measured values of S ψφ and a s sl within their 1σ ranges. On the other hand, in the Z ′ FCNC model, the values of all three observables can be simultaneously reproduced.