Measurement of the $\mathit{W}\to \mathit{\tau }\mathit{\nu }$ Production Cross Section in $\mathit{p}\overline{\mathit{p}}$ Collisions at $\sqrt{\mathit{s}}=1.8\mathrm{}\mathrm{TeV}$

We report on a measurement of $\sigma (p\overline{p}\to W+X)B(W\to \tau \nu )$ in $p\overline{p}$ collisions at $\sqrt{s}=1.8\mathrm{}\mathrm{TeV}$ at the Fermilab Tevatron. The measurement is based on an integrated luminosity (lum) of $18{\mathrm{pb}}^{-1\mathrm{}}$ of data collected with the D0 detector during 1994–1995. We find that $\sigma (p\overline{p}\to W+X)B(W\to \tau \nu )=2.22\mathrm{}\pm 0.09\left(\mathrm{stat}\right)\pm 0.10\left(\mathrm{syst}\right)\pm 0.10\left(\mathrm{lum}\right)\mathrm{nb}$. Lepton universality predicts that the ratio of the tau and electron electroweak charged current couplings to the $W$ boson, $g_{\tau }^W{/g}_e^W$, be unity. We find $g_{\tau }^W{/g}_e^W=0.980\mathrm{}\pm 0.031$, in agreement with lepton universality.