Measurement of $\mathbf{\sigma }(\mathbf{p}\bar{\mathbf{p}}\to \mathbf{Z})\cdot$Br$(\mathbf{Z}\to \mathbf{\tau \tau })$ at $\sqrt{\mathbf{s}}=$1.96 TeV

Abstract

We present a measurement of the cross section for $Z$ production times the branching fraction to $\tau$ leptons, $\sigma \cdot$Br$(Z\to {\tau }^{+}{\tau }^{-})$, in $p\bar{p}$ collisions at $\sqrt{s}=$1.96 TeV in the channel in which one $\tau$ decays into $\mu {\nu }_{\mu }{\nu }_{\tau }$, and the other into $\mathrm{hadrons}+{\nu }_{\tau }$ or $e{\nu }_e{\nu }_{\tau }$. The data sample corresponds to an integrated luminosity of 226 pb${}^{-1}$ collected with the DØdetector at the Fermilab Tevatron collider. The final sample contains 2008 candidate events with an estimated background of 55%. From this we obtain $\sigma \cdot$Br$(Z\to {\tau }^{+}{\tau }^{-})=237\pm 15$(stat)$\pm 18$(sys)$\pm 15$(lum) pb, in agreement with the standard model prediction.