  Tagged jet measurements provide a promising experimental channel to quantify
the similarities and differences in the mechanisms of jet production in
proton-proton and nucleus-nucleus collisions. We present the first calculation
of the transverse momentum asymmetry of $Z^0/\gamma^*$-tagged jet events and
the momentum imbalance of $\gamma$-tagged jet events in $\sqrt{s}=2.76$ TeV
reactions at the LHC. Our results combine the ${\cal O}(G_F\alpha_s^2)$, ${\cal
O}(G_F\alpha_s^2)$ perturbative cross sections with the radiative and
collisional processes that modify parton showers in the presence of dense QCD
matter. We find that strong asymmetry momentum and imbalance, respectively, are
generated in central Pb+Pb reactions that have little sensitivity to the
fluctuations of the underlying soft hadronic background. We present theoretical
model predictions for their shape and magnitude.
