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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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