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\label{sec:gen} |
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\subsection{Monte Carlo generators} |
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The signal and background samples for the full detector simulation |
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were generated with the leading order event generator PYTHIA~\cite{Sjostrand:2003wg}, ALPGEN or COMPHEP. To |
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accommodate NLO effect constant k-factors were applied. |
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< |
Additionally the cross section calculator MCFM~\cite{Campbell:2005} was used to determine |
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< |
the next-to-leading order differential cross section for the WZ |
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production process. To estimate the PDF uncertainty for the signal |
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process at NLO the NLO event generator MC@NLO 3.1~\cite{Frixione:2002ik} together with PDF set |
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CTEQ6M was used. |
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are generated with the leading order event generator |
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> |
{\sl PYTHIA}~\cite{Sjostrand:2003wg}, {\sl ALPGEN} and {\sl COMPHEP}. |
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> |
To accommodate next-to-leading (NLO) effects, constant $k$-factors are applied. |
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> |
Additionally, the cross section calculator {\sl MCFM}~\cite{Campbell:2005} |
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> |
is used to determine the NLO differential cross section for the $\WZ$ |
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> |
production. To estimate the uncertainty on the cross-section |
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due to the choice of the PDF, we use NLO event generator |
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{\sl MC@NLO 3.1}~\cite{Frixione:2002ik} together with CTEQ6M PDF set. |
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|
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\subsection{Signal Definition} |
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\subsection{Signal definition} |
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|
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The goal of the analysis is to study the final state of on-shell $W$ |
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and $Z$ boson, both of them decaying leptonically. The leptonic final |
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state $l^+ l^- l^\pm \nu$ also receives a contribution from the |
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$W\gamma *$ process, where the $\gamma *$ stands for a virtual photon |
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through the $WW\gamma$ vertex. In this analysis, only events with $l^+ |
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l^-$ invariant mass consistent with $Z$ mass will be considered. CMS |
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detector have a very good energy resolution for electrons and muons, |
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the mass windows will be $\pm 10$ GeV around 91 GeV. |
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The goal of this analysis is to study the associative production of the on-shell |
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> |
$W$ and $\Z$ bosons that decay into three leptons and a neutrino. In the |
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> |
following we refer to a lepton to as either a muon or an electron, unless |
| 19 |
> |
specified otherwise. The leptonic final state $\ell^+ \ell^- \ell^\pm \nu$ also receives a |
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> |
contribution from the $W\gamma^*$ production, where the $\gamma^*$ stands for a |
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> |
virtual photon through the $WW\gamma$ vertex. In this analysis, we |
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restrict this contribution by requiring the $\ell^\ell^-$ invariant mass to be |
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consistent with the nominal $\Z$ boson mass. As CMS detector has a very |
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> |
good energy resolution for electrons and muons, the mass window |
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is set to be $\pm$ 10 GeV around 91 GeV. |
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> |
|
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%%%%%%%%%%%%%%% |
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% YM modified before this mark |
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|
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Using MCFM to estimate the total NLO cross section, we found: |
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\begin{equation} |
