Observation of Top Quark Production inp¯pCollisions with the Collider Detector at Fermilab

We establish the existence of the top quark using a $67{\mathrm{pb}}^{-1\mathrm{}}$ data sample of $\overline{p}p$ collisions at $\sqrt{s}=1.8\mathrm{}\mathrm{TeV}$ collected with the Collider Detector at Fermilab (CDF). Employing techniques similar to those we previously published, we observe a signal consistent with $t\overline{t}$ decay to $\mathrm{WWb}\overline{b}$, but inconsistent with the background prediction by $4.8\sigma$. Additional evidence for the top quark is provided by a peak in the reconstructed mass distribution. We measure the top quark mass to be $176\pm 8\left(\mathrm{stat}\right)\pm 10\left(\mathrm{syst}\right)\mathrm{GeV}{/c}^2$, and the $t\overline{t}$ production cross section to be ${6.8}_{-2.4\mathrm{}}^{+3.6\mathrm{}}\mathrm{pb}$.