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\section{Conclusions and perspectives}
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\label{sec:conclusions}
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We have investigated the sensitivity of the CMS experiment
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to the detection and study of the $\proton\proton\to\W\Z\to 3 \ell$ process.
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Signal and background samples were processed through full simulation,
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reconstruction and analysis chain of CMS.
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The present analysis expects a yield of 140 signal for 228 background events per inverse
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femtobarn of LHC integrated luminosity. Chances are therefore that first observation of
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\WZ\ pair production in hadron collisions will be achieved by the end of the first CMS
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physics run. We estimate a statistical significance $S_L\simeq 8.5 $ for 1~\invfb.
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We have developed methods for measuring the background yield from data. This
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is especially important for substracting the dominant background coming from
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events with a genuine \Z boson.
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The largest challenge in the background suppression has proved to be the
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rejection of fake electrons originating from hadronic jets or photons. Even
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though less problematic, the rejection of true leptons from heavy quark
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decays is also an important key in reducing the background. Further work will
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need to be done in these directions.
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The presence of the neutrino in the \WZ signal, resulting in large missing energy,
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has not been used so far, but the missing energy or the W transverse mass could
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prove as a powerful tool for a better signal extraction in the future.
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The relatively large signal yield and low level of background for the
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the $\WZ\to 3l$ mode makes it particularly attractive
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for the study of anomalous neutral triple gauge boson couplings, which should
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be made possible already with a few inverse femtobarns.
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