  Perturbative unitarity conditions have been playing an important role by
estimating the energy scale of new physics, including the Higgs mass as one of
the most important examples. In this letter, we show that there is a
possibility to see the hint of a new physics (top quark partner) indirectly by
observing an "apparent" unitarity violation in $M_{bw}$ distribution well above
top quark mass in a process of a heavy resonance decaying into a pair of top
quarks.
