  We present a measurement of the direct CP-violating charge asymmetry in B^+/-
mesons decaying to J/psi K^+/- and J/psi pi^+/- where J/psi decays to mu^+
mu^-, using the full Run II data set of 10.4 fb^-1 of proton-antiproton
collisions collected using the D0 detector at the Fermilab Tevatron Collider. A
difference in the yield of B^- and B^+ mesons in these decays is found by
fitting to the difference between their reconstructed invariant mass
distributions resulting in asymmetries of ajpk =[0.59 +/- 0.37]%, which is the
most precise measurement to date, and ajppi= [-4.2 +/- 4.5]%. Both measurements
are consistent with standard model predictions.
