Measurement of W to tau-nu

The cross--section of $W$$\rightarrow$$\tau\nu$ production is measured in $pp$ collisions at $\sqrt{s} = 7$~TeV with data collected by the CMS experiment corresponding to a luminosity of $32.4$~pb$^{-1}$. Tau leptons are identified via their hadronic decays. The measured cross--section is $\sigma ( pp$$\rightarrow$$W X ) \times \mathcal{B} ( W$$\rightarrow$$\tau \nu ) = 8.96 \pm 0.51 \mathrm{(stat.)}^{+2.32}_{-2.26} \mathrm{(sys.)} \pm 0.36 \mathrm{(lumi.)}$~nb. The ratio of $W^{+}$$\rightarrow$$\tau^{+}\nu$ to $W^{-}$$\rightarrow\tau^{-}$$\nu$ cross--sections is measured to be $1.55 \pm 0.19 \mathrm{(stat.)}^{+0.11}_{-0.13} \mathrm{(sys.)}$. The result is in agreement with NNLO theory prediction.