Understanding the like-sign dimuon charge asymmetry in pp̄ collisions

The D0 Collaboration has measured the like-sign dimuon charge asymmetry in pp̄ collisions at the Fermilab Tevatron collider. The result is significantly different from the standard model expectation of CP violation in mixing. In this paper we consider the possible causes of this asymmetry and identify one standard model source not considered before, namely, CP violation in interference of decays of B0 with and without mixing to flavor nonspecific states f_i, followed by the decay f_i→μX. The discrepancy between the D0 measurement and the standard model expectation is reduced to less than 3 standard deviations.