  We propose two new observables to measure the charge asymmetry in hadronic
top-quark pair production in association with a hard jet. The incline
asymmetry, based on the inclination between the planes of initial- and
final-state momenta, probes the charge asymmetry in the quark-antiquark
channel. Compared to the hitherto investigated rapidity asymmetries, the
incline asymmetry provides improved access to the partonic charge asymmetry at
both the Tevatron and the LHC. The energy asymmetry, based on the energy
difference between top and antitop quarks, for the first time allows us to
probe the charge asymmetry in the quark-gluon channel at the LHC. In quantum
chromodynamics, asymmetries of up to -12% at the leading order are achievable
with appropriate cuts. Top-pair plus jet production thus has the potential to
become the discovery channel of the charge asymmetry in proton-proton
collisions.
