| 1 |
\section{Event selection and Lepton ID}
|
| 2 |
\label{sec:selection}
|
| 3 |
|
| 4 |
\subsection{General event requirements}
|
| 5 |
\label{sec:evselection}
|
| 6 |
|
| 7 |
\subsubsection{Trigger requirements}
|
| 8 |
\label{sec:trigger}
|
| 9 |
{\color{red}
|
| 10 |
Dielectron events come from the EG Secondary/Primary datasets
|
| 11 |
and are required to pass the HLT\_Photon10\_L1R trigger.
|
| 12 |
Dimuon events come from the MU Secondary/Primary datasets
|
| 13 |
and are required to pass the HLT\_Mu5 trigger.
|
| 14 |
Finally, $e\mu$ events can come from either the EG or MU
|
| 15 |
Secondary/Primary datasets, and are required to pass
|
| 16 |
either the HLT\_Photon10\_L1R or HLT\_Mu5 trigger.
|
| 17 |
Care has been taken to not double count events appearing
|
| 18 |
in both datasets.
|
| 19 |
}
|
| 20 |
|
| 21 |
{\color{blue}
|
| 22 |
Dielectron events come from the EG Secondary/Primary datasets
|
| 23 |
and are required to pass one of the following triggers
|
| 24 |
\begin{itemize}
|
| 25 |
\item HLT\_Photon10\_L1R
|
| 26 |
\item HLT\_Photon10\_Cleaned\_L1R
|
| 27 |
\item HLT\_Photon15\_L1R
|
| 28 |
\item HLT\_Photon15\_Cleaned\_L1R
|
| 29 |
\item HLT\_Ele10\_LW\_L1R
|
| 30 |
\end{itemize}
|
| 31 |
Dimuon events come from the MU Secondary/Primary datasets
|
| 32 |
and are required to pass the HLT\_Mu5 trigger.
|
| 33 |
Finally, $e\mu$ events can come from either the EG or MU
|
| 34 |
Secondary/Primary datasets, and are required to pass
|
| 35 |
any of the triggers mentioned above.
|
| 36 |
Care has been taken to not double count events appearing
|
| 37 |
in both datasets. The complicated EG trigger path
|
| 38 |
is due to evolving trigger conditions.
|
| 39 |
}
|
| 40 |
|
| 41 |
|
| 42 |
\subsubsection{Event Cleanup}
|
| 43 |
\label{sec:cleanup}
|
| 44 |
We apply the standard ``goodrun'' list. In addition:
|
| 45 |
\begin{itemize}
|
| 46 |
\item Require BPTX bit 0.
|
| 47 |
\item Veto beam halo bits (36,37,38,39).
|
| 48 |
\item Scraping cut: if there are $\geq$ 10 tracks, require at
|
| 49 |
least 25\% of them to be high purity.
|
| 50 |
\item Require at least one good vertex:
|
| 51 |
\begin{itemize}
|
| 52 |
\item not fake
|
| 53 |
\item ndof $>$ 4
|
| 54 |
\item $|\rho| < 2$ cm
|
| 55 |
\item $|z| < 15$ cm.
|
| 56 |
\end{itemize}
|
| 57 |
\end{itemize}
|
| 58 |
|
| 59 |
\subsubsection{$Z$ removal}
|
| 60 |
\label{sec:zremoval}
|
| 61 |
We remove $e^+e^-$ and $\mu^+\mu^-$ events with invariant mass
|
| 62 |
bewteen 76 and 106 GeV. This is because our present focus
|
| 63 |
is to understand OS events off the $Z$ peak.
|
| 64 |
|
| 65 |
We also remove SS $ee$ pairs consistent with the $Z$. This
|
| 66 |
is because we know that electron charge misidentification
|
| 67 |
is an important effect. On the MC we have developed
|
| 68 |
data driven method to estimate these backgrounds\cite{ref:SSSusy}
|
| 69 |
starting from the $Z \to e^+e^-$ sample. We do not have enough
|
| 70 |
Zs in the data to carry out this program yet.
|
| 71 |
|
| 72 |
|
| 73 |
|
| 74 |
|
| 75 |
\subsubsection{Electron requirements}
|
| 76 |
\label{sec:eleID}
|
| 77 |
Electron candidates are RECO GSF electrons passing the following
|
| 78 |
requirements:
|
| 79 |
|
| 80 |
\begin{itemize}
|
| 81 |
|
| 82 |
\item $P_T > 10$ GeV.
|
| 83 |
|
| 84 |
\item $|\eta| < 2.5$.
|
| 85 |
|
| 86 |
\item SuperCluster $E_T > 10$ GeV; this requirement is made for
|
| 87 |
consistency with the photon trigger.
|
| 88 |
|
| 89 |
\item The electron must be ecal seeded.
|
| 90 |
|
| 91 |
\item VBTF90 identification\cite{ref:vbtf}.
|
| 92 |
|
| 93 |
\item Transverse impact parameter with respect to the beamspot $<$ 400 $\mu$m.
|
| 94 |
|
| 95 |
\item $Iso \equiv $ $E_T^{\rm iso}$/Max(20 GeV, $P_T$) $<$ 0.15.
|
| 96 |
$E_T^{\rm iso}$
|
| 97 |
is defined as the sum of transverse energy/momentum deposits in ecal,
|
| 98 |
hcal, and tracker, in a
|
| 99 |
cone of 0.3. A 1 GeV pedestal is subtracted from the ecal energy
|
| 100 |
deposition in the EB, however the ecal energy is never allowed to
|
| 101 |
go negative.
|
| 102 |
|
| 103 |
\item Electrons with a tracker or global muon within $\Delta R$ of
|
| 104 |
0.1 are vetoed.
|
| 105 |
|
| 106 |
\item The number of missing expected inner hits must be less than
|
| 107 |
two\cite{ref:conv}.
|
| 108 |
|
| 109 |
\item Conversion removal via partner track finding: any electron
|
| 110 |
where an additional GeneralTrack is found with $Dist < 0.02$ cm
|
| 111 |
and $\Delta \cot \theta < 0.02$ is vetoed\cite{ref:conv}.
|
| 112 |
|
| 113 |
{\color{blue}
|
| 114 |
\item Cleaning for ECAL spike (aka Swiss-Cross cleaning) has been applied.
|
| 115 |
This new requirement rejects only of order 1\% of electron candidates and
|
| 116 |
was added to harmonize our selection with the dilepton analysis in
|
| 117 |
the top group.
|
| 118 |
}
|
| 119 |
|
| 120 |
\end{itemize}
|
| 121 |
|
| 122 |
|
| 123 |
\subsubsection{Muon requirements}
|
| 124 |
\label{sec:muID}
|
| 125 |
Muon candidates are RECO muon objects passing the following
|
| 126 |
requirements:
|
| 127 |
|
| 128 |
\begin{itemize}
|
| 129 |
|
| 130 |
\item $P_T > 10$ GeV.
|
| 131 |
|
| 132 |
\item $|\eta| < 2.5$.
|
| 133 |
|
| 134 |
\item Global Muon and Tracker Muon.
|
| 135 |
|
| 136 |
\item $\chi^2$/ndof of global fit $<$ 10.
|
| 137 |
|
| 138 |
\item At least 11 hits in the tracker fit.
|
| 139 |
|
| 140 |
\item Transverse impact parameter with respect to the beamspot $<$ 200 $\mu$m.
|
| 141 |
|
| 142 |
\item $Iso \equiv $ $E_T^{\rm iso}$/Max(20 GeV, $P_T$) $<$ 0.15.
|
| 143 |
$E_T^{\rm iso}$
|
| 144 |
is defined as the sum of transverse energy/momentum deposits in ecal,
|
| 145 |
hcal, and tracker, in a cone of 0.3.
|
| 146 |
|
| 147 |
{\color{blue} \item At least one of the hits from the
|
| 148 |
standalone muon must be used in the global fit.
|
| 149 |
This new requirement rejects of order 10\% of muon candidates
|
| 150 |
in QCD and
|
| 151 |
was added to harmonize our selection with the dilepton analysis in
|
| 152 |
the top group.
|
| 153 |
}
|
| 154 |
|
| 155 |
\end{itemize}
|
| 156 |
|
| 157 |
|
| 158 |
|
| 159 |
|
