Limits on Lepton-quark contact interactions from the quark forward-backward asymmetry in e+e- annihilation
Lepton-quark contact interactions expected in composite theories can be tested using the forward-backward (F-B) asymmetry of charm or bottom hadrons in e+e- annihilation. Existing data on the F-B asymmetry of D* and D mesons can already set lower limits typically exceeding 1 TeV (95% CL) on the compositeness scale. These limits are better than those for pure quark contact interactions set by the CERN pp̄ collider experiments, and are comparable to purely leptonic ones obtained in e+e- annihilation experiments. The implication of bottom quark asymmetry in the presence of B0-B0 mixing is also briefly discussed.