We present evidence for hadronic W decays in $t\bar t\ \to$ lepton + neutrino + $\ge$ 4 jet events using a 109 pb$\sp{-1}$ data sample of $p\bar p$ collisions at $\sqrt s$ = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). A peak in the dijet invariant mass distribution is obtained in events where two b jets are identified. This peak is consistent with W decay but inconsistent with the predicted background shape by 2.9$\sigma$. We measure the W mass to be 78.3 $\pm$ 5.1 (stat) $\pm$ 3.0 (syst) GeV/$c\sp2$. This result demonstrates the presence of a second W in these $t\bar t$ candidates. We show ways in which this result can be used to study $t\bar t$ events and detector calibration, for present and future datasets.
We also search for hadronic decay modes from direct W and Z production, but find no stable signal, due to trigger inefficiency.
