Unitarity Constraints on Anomalous Top Quark Couplings to Weak Gauge Bosons

If there is new physics associated with the top quark, it could show up as anomalous couplings of the top quark, such as $Z\ttbar$ and $W\tbbar$ vector and axial-vector couplings. We use the processes $\ttbar\to Z^0Z^0$, $\ttbar\to W^+W^-$, and $\ttbar\to Z^0H$ to obtain the unitarity constraints on these anomalous couplings, and combine these constraints with those from precision electroweak data. A nonzero measurement of such an anomalous coupling will put an upper limit on the new physics scale by the unitarity condition.