  A D0 analysis measuring the charge asymmetry Ab_sl of like-sign dimuon events
due to semileptonic b-hadron decays at the Fermilab Tevatron Collider has shown
indications of possible anomalous CP violation in the mixing of neutral B
mesons. This result has been used to extract the first senstivity to CPT
violation in the B0_s system. A procedure to explore further this anomaly by
specifically measuring the semileptonic charge asymmetry, as_sl, in B0_s decays
is described, as well as how a variant of this analysis can be used to explore
a larger set of CPT-violating parameters in the B0_s system for the first time.
