The recent measurement of the like-sign dimuon charge asymmetry in semileptonic b-hadron decays by the D0 Collaboration is about three sigmas away from the standard-model prediction, hinting at the presence of CP-violating new physics in the mixing of B(s) mesons. We consider the possibility that this anomalous result arises from the contribution of a light spin-1 particle. Taking into account various experimental constraints, we find that the effect of such a particle with mass below the b-quark mass can yield a prediction consistent with the anomalous DO measurement within its one-sigma range. (C) 2011 Elsevier B.V. All rights reserved.
