D0 dimuon charge asymmetry from B_s system with Z ^′ couplings and the recent LHCb result

The D0 collaboration has announced the observation of the like-sign dimuon charge asymmetry since 2010, which has a difference of more than 3σ from the Standard Model prediction. One of the promising explanations is considering the existence of flavor-changing Z^′ couplings to the b and s quarks which can contribute to the off-diagonal decay width in the B _s-B_̄s mixing. Model construction is highly constrained by the recent LHCb data of 1 fb^-1 integrated luminosity. In this paper, we analyze the experimental constraints on constructing new physics models to explain the dimuon charge asymmetry from the CP violation of the B_s system. We present limits on Z^′ couplings and show that it is impossible to obtain the 1σ range of the dimuon charge asymmetry without the new contribution in the B_d system. Even with an arbitrary contribution in the B_d system, the new couplings must be in the fine-tuned region.