  The D\O\ collaboration has measured the like-sign dimuon charge asymmetry in
$p \bar{p}$ 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. It decreases the
discrepancy of the like-sign dimuon charge asymmetry with the standard model
prediction, although does not eliminate it completely.
