| 1 |
claudioc |
1.1 |
\section{Event Preselection}
|
| 2 |
|
|
\label{sec:eventSel}
|
| 3 |
|
|
{\color{red} This needs to be fixed up -- probably many mistakes present.}\\
|
| 4 |
|
|
As mentioned in the introduction, the preselection is based on the
|
| 5 |
|
|
$t\bar{t}$ analysis. We select events with two opposite sign isolated
|
| 6 |
|
|
leptons ($ee$, $e\mu$, or $\mu\mu$); one of the leptons must
|
| 7 |
|
|
have $P_T > 20$ GeV,
|
| 8 |
|
|
the other one must have $P_T > 10$ GeV; there must be two JPT
|
| 9 |
claudioc |
1.3 |
jets of $P_T > 30$ GeV and $|\eta| <$ {\color{red} xx}; the scalar sum of the
|
| 10 |
|
|
$P_T$ of all such jets must exceed 100 GeV; finally $\met > 50$ GeV
|
| 11 |
claudioc |
1.1 |
(we use tcMet). More details are given in the subsection below.
|
| 12 |
|
|
|
| 13 |
|
|
\subsection{Event Cleanup}
|
| 14 |
|
|
\label{sec:cleanup}
|
| 15 |
|
|
\begin{itemize}
|
| 16 |
|
|
\item Scraping cut: if there are $\geq$ 10 tracks, require at
|
| 17 |
|
|
least 25\% of them to be high purity.
|
| 18 |
|
|
\item Require at least one good vertex:
|
| 19 |
|
|
\begin{itemize}
|
| 20 |
|
|
\item not fake
|
| 21 |
|
|
\item ndof $>$ 4
|
| 22 |
|
|
\item $|\rho| < 2$ cm
|
| 23 |
claudioc |
1.3 |
\item $|z| < 24$ cm.
|
| 24 |
claudioc |
1.1 |
\end{itemize}
|
| 25 |
|
|
\end{itemize}
|
| 26 |
|
|
|
| 27 |
|
|
|
| 28 |
|
|
\subsection{Muon Selection}
|
| 29 |
|
|
\label{sec:muon}
|
| 30 |
|
|
|
| 31 |
|
|
Muon candidates are RECO muon objects passing the following
|
| 32 |
|
|
requirements:
|
| 33 |
|
|
\begin{itemize}
|
| 34 |
|
|
|
| 35 |
|
|
\item $|\eta| < 2.5$.
|
| 36 |
|
|
|
| 37 |
|
|
\item Global Muon and Tracker Muon.
|
| 38 |
|
|
|
| 39 |
|
|
\item $\chi^2$/ndof of global fit $<$ 10.
|
| 40 |
|
|
|
| 41 |
|
|
\item At least 11 hits in the tracker fit.
|
| 42 |
|
|
|
| 43 |
|
|
\item Transverse impact parameter with respect to the beamspot $<$ 200 $\mu$m.
|
| 44 |
|
|
|
| 45 |
|
|
\item $Iso \equiv $ $E_T^{\rm iso}$/Max(20 GeV, $P_T$) $<$ 0.15.
|
| 46 |
|
|
$E_T^{\rm iso}$
|
| 47 |
|
|
is defined as the sum of transverse energy/momentum deposits in ecal,
|
| 48 |
|
|
hcal, and tracker, in a cone of 0.3.
|
| 49 |
|
|
|
| 50 |
|
|
\item At least one of the hits from the
|
| 51 |
|
|
standalone muon must be used in the global fit.
|
| 52 |
|
|
|
| 53 |
|
|
\end{itemize}
|
| 54 |
|
|
|
| 55 |
|
|
|
| 56 |
|
|
|
| 57 |
claudioc |
1.2 |
\subsection{Electron Selection}
|
| 58 |
claudioc |
1.1 |
\label{sec:electron}
|
| 59 |
|
|
|
| 60 |
|
|
Electron candidates are RECO GSF electrons passing the following
|
| 61 |
|
|
requirements:
|
| 62 |
|
|
|
| 63 |
|
|
\begin{itemize}
|
| 64 |
|
|
|
| 65 |
|
|
\item $P_T > 10$ GeV. (The $t\bar{t}$ analysis uses 20 GeV but for
|
| 66 |
|
|
completeness we calculate FR down to 10 GeV).
|
| 67 |
|
|
|
| 68 |
|
|
\item $|\eta| < 2.5$.
|
| 69 |
|
|
|
| 70 |
|
|
\item SuperCluster $E_T > 10$ GeV.
|
| 71 |
|
|
|
| 72 |
|
|
\item The electron must be ecal seeded.
|
| 73 |
|
|
|
| 74 |
|
|
\item VBTF90 identification\cite{ref:vbtf}.
|
| 75 |
|
|
|
| 76 |
|
|
\item Transverse impact parameter with respect to the beamspot $<$ 400 $\mu$m.
|
| 77 |
|
|
|
| 78 |
|
|
\item $Iso \equiv $ $E_T^{\rm iso}$/Max(20 GeV, $P_T$) $<$ 0.15.
|
| 79 |
|
|
$E_T^{\rm iso}$
|
| 80 |
|
|
is defined as the sum of transverse energy/momentum deposits in ecal,
|
| 81 |
|
|
hcal, and tracker, in a
|
| 82 |
|
|
cone of 0.3. A 1 GeV pedestal is subtracted from the ecal energy
|
| 83 |
|
|
deposition in the EB, however the ecal energy is never allowed to
|
| 84 |
|
|
go negative.
|
| 85 |
|
|
|
| 86 |
|
|
\item Electrons with a tracker or global muon within $\Delta R$ of
|
| 87 |
|
|
0.1 are vetoed.
|
| 88 |
|
|
|
| 89 |
|
|
\item The number of missing expected inner hits must be less than
|
| 90 |
|
|
two\cite{ref:conv}.
|
| 91 |
|
|
|
| 92 |
|
|
\item Conversion removal via partner track finding: any electron
|
| 93 |
|
|
where an additional GeneralTrack is found with $Dist < 0.02$ cm
|
| 94 |
|
|
and $\Delta \cot \theta < 0.02$ is vetoed\cite{ref:conv}.
|
| 95 |
|
|
|
| 96 |
claudioc |
1.4 |
\item Cleaning for ECAL spike (aka Swiss-Cross cleaning) has been applied
|
| 97 |
|
|
at the reconstruction level (CMSSW 38x).
|
| 98 |
claudioc |
1.1 |
|
| 99 |
|
|
\end{itemize}
|
| 100 |
|
|
|
| 101 |
claudioc |
1.2 |
\subsection{Z veto}
|
| 102 |
|
|
\label{sec:zveto}
|
| 103 |
|
|
|
| 104 |
|
|
We remove $e^+e^-$ and $\mu^+ \mu^-$ events with invariant
|
| 105 |
claudioc |
1.4 |
mass between 76 and 106 GeV.
|
| 106 |
claudioc |
1.2 |
|
| 107 |
|
|
|
| 108 |
|
|
\subsection{Trigger Selection}
|
| 109 |
claudioc |
1.1 |
\label{sec:trigSel}
|
| 110 |
|
|
|
| 111 |
|
|
Because most of the triggers implemented in the 2nd half of the
|
| 112 |
|
|
2010 run were not implemented in the Monte Carlo, no trigger
|
| 113 |
|
|
selection is applied on Monte Carlo data. As discussed in
|
| 114 |
|
|
Section~\ref{sec:trgEff}, a trigger efficiency weight is applied
|
| 115 |
|
|
to each event, based on the trigger efficiencies measured on data.
|
| 116 |
|
|
Trigger efficiency weights are very close to 1.
|
| 117 |
|
|
|
| 118 |
|
|
For data, we require the logical OR of all (or most?) unprescaled
|
| 119 |
|
|
single and double lepton triggers that were deployed during the 2010
|
| 120 |
|
|
run. These are:
|
| 121 |
|
|
{\color{red} Here we need to list the triggers, somehow.}
|
| 122 |
|
|
|
