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Committed: Wed Nov 3 23:05:17 2010 UTC (14 years, 6 months ago) by claudioc
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# Content
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\footnote{In case of events with
9 more than two such leptons, we select the pair that maximizes the scalar
10 sum of lepton $P_T$'s.};
11 there must be two JPT
12 jets of $P_T > 30$ GeV and $|\eta| < 2.5$; the scalar sum of the
13 $P_T$ of all such jets must exceed 100 GeV; jets must pass
14 {\tt caloJetId} and be separated by $\Delta R >$ 0.4 from the
15 two leptons. Finally $\met > 50$ GeV
16 (we use tcMet). More details are given in the subsection below.
17
18 \subsection{Event Cleanup}
19 \label{sec:cleanup}
20 \begin{itemize}
21 \item Scraping cut: if there are $\geq$ 10 tracks, require at
22 least 25\% of them to be high purity.
23 \item Require at least one good vertex:
24 \begin{itemize}
25 \item not fake
26 \item ndof $>$ 4
27 \item $|\rho| < 2$ cm
28 \item $|z| < 24$ cm.
29 \end{itemize}
30 \end{itemize}
31
32
33 \subsection{Muon Selection}
34 \label{sec:muon}
35
36 Muon candidates are RECO muon objects passing the following
37 requirements:
38 \begin{itemize}
39
40 \item $|\eta| < 2.4$.
41
42 \item Global Muon and Tracker Muon.
43
44 \item $\chi^2$/ndof of global fit $<$ 10.
45
46 \item At least 11 hits in the tracker fit.
47
48 \item Transverse impact parameter with respect to the beamspot $<$ 200 $\mu$m.
49
50 \item $Iso \equiv $ $E_T^{\rm iso}$/Max(20 GeV, $P_T$) $<$ 0.15.
51 $E_T^{\rm iso}$
52 is defined as the sum of transverse energy/momentum deposits in ecal,
53 hcal, and tracker, in a cone of 0.3.
54
55 \item At least one of the hits from the
56 standalone muon must be used in the global fit.
57
58 \end{itemize}
59
60
61
62 \subsection{Electron Selection}
63 \label{sec:electron}
64
65 Electron candidates are RECO GSF electrons passing the following
66 requirements:
67
68 \begin{itemize}
69
70 \item $P_T > 10$ GeV. (The $t\bar{t}$ analysis uses 20 GeV but for
71 completeness we calculate FR down to 10 GeV).
72
73 \item $|\eta| < 2.5$.
74
75 \item SuperCluster $E_T > 10$ GeV.
76
77 \item The electron must be ecal seeded.
78
79 \item VBTF90 identification\cite{ref:vbtf}.
80
81 \item Transverse impact parameter with respect to the beamspot $<$ 400 $\mu$m.
82
83 \item $Iso \equiv $ $E_T^{\rm iso}$/Max(20 GeV, $P_T$) $<$ 0.15.
84 $E_T^{\rm iso}$
85 is defined as the sum of transverse energy/momentum deposits in ecal,
86 hcal, and tracker, in a
87 cone of 0.3. A 1 GeV pedestal is subtracted from the ecal energy
88 deposition in the EB, however the ecal energy is never allowed to
89 go negative.
90
91 \item Electrons with a tracker or global muon within $\Delta R$ of
92 0.1 are vetoed.
93
94 \item The number of missing expected inner hits must be less than
95 two\cite{ref:conv}.
96
97 \item Conversion removal via partner track finding: any electron
98 where an additional GeneralTrack is found with $Dist < 0.02$ cm
99 and $\Delta \cot \theta < 0.02$ is vetoed\cite{ref:conv}.
100
101 \item Cleaning for ECAL spike (aka Swiss-Cross cleaning) has been applied
102 at the reconstruction level (CMSSW 38x).
103
104 \end{itemize}
105
106 \subsection{Invariant mass requirement}
107 \label{sec:zveto}
108
109 We remove $e^+e^-$ and $\mu^+ \mu^-$ events with invariant
110 mass between 76 and 106 GeV. We also remove events
111 with invariant mass $<$ 10 GeV.
112
113 \subsection{Trigger Selection}
114 \label{sec:trigSel}
115
116 Because most of the triggers implemented in the 2nd half of the
117 2010 run were not implemented in the Monte Carlo, no trigger
118 selection is applied on Monte Carlo data. As discussed in
119 Section~\ref{sec:trgEff}, a trigger efficiency weight is applied
120 to each event, based on the trigger efficiencies measured on data.
121 Trigger efficiency weights are very close to 1.
122
123 %For data, we require the logical OR of all (or most?) unprescaled
124 %single and double lepton triggers that were deployed during the 2010
125 %run. These are:
126 %{\color{red} Here we need to list the triggers, somehow.}
127
128 For data, we use a cocktail of unprescaled single
129 and double lepton triggers. An event
130 in the $ee$ final state is required to pass at least 1
131 single- or double-electron trigger, a
132 $\mu\mu$ event is required to pass at least 1 single
133 or double-muon trigger, while an $e\mu$ event
134 is required to pass at least 1 single-muon, single-electron,
135 or $e-\mu$ cross trigger.
136 % We currently
137 % do not require MC events to pass any triggers.
138
139 \begin{itemize}
140 \item single-muon triggers
141 \begin{itemize}
142 \item \verb=HLT_Mu5=
143 \item \verb=HLT_Mu7=
144 \item \verb=HLT_Mu9=
145 \item \verb=HLT_Mu11=
146 \item \verb=HLT_Mu13_v1=
147 \item \verb=HLT_Mu15_v1=
148 \item \verb=HLT_Mu17_v1=
149 \item \verb=HLT_Mu19_v1=
150 \end{itemize}
151 \item double-muon triggers
152 \begin{itemize}
153 \item \verb=HLT_DoubleMu3=
154 \item \verb=HLT_DoubleMu3_v2=
155 \item \verb=HLT_DoubleMu5_v1=
156 \end{itemize}
157 \item single-electron triggers
158 \begin{itemize}
159 \item \verb=HLT_Ele10_SW_EleId_L1R=
160 \item \verb=HLT_Ele10_LW_EleId_L1R=
161 \item \verb=HLT_Ele10_LW_L1R=
162 \item \verb=HLT_Ele10_SW_L1R=
163 \item \verb=HLT_Ele15_SW_CaloEleId_L1R=
164 \item \verb=HLT_Ele15_SW_EleId_L1R=
165 \item \verb=HLT_Ele15_SW_L1R=
166 \item \verb=HLT_Ele15_LW_L1R=
167 \item \verb=HLT_Ele17_SW_TightEleId_L1R=
168 \item \verb=HLT_Ele17_SW_TighterEleId_L1R_v1=
169 \item \verb=HLT_Ele17_SW_CaloEleId_L1R=
170 \item \verb=HLT_Ele17_SW_EleId_L1R=
171 \item \verb=HLT_Ele17_SW_LooseEleId_L1R=
172 \item \verb=HLT_Ele17_SW_TighterEleIdIsol_L1R_v2=
173 \item \verb=HLT_Ele20_SW_L1R=
174 \item \verb=HLT_Ele22_SW_TighterEleId_L1R_v2=
175 \item \verb=HLT_Ele32_SW_TightCaloEleIdTrack_L1R_v1=
176 \item \verb=HLT_Ele32_SW_TighterEleId_L1R_v2=
177 \item \verb=HLT_Ele27_SW_TightCaloEleIdTrack_L1R_v1=
178 \item \verb=HLT_Ele22_SW_TighterCaloIdIsol_L1R_v2=
179 \item \verb=HLT_Ele22_SW_TighterEleId_L1R_v3=
180 \item \verb=HLT_Ele22_SW_TighterCaloIdIsol_L1R_v2=
181 \end{itemize}
182 \item double-electron triggers
183 \begin{itemize}
184 \item \verb=HLT_DoubleEle15_SW_L1R_v1=
185 \item \verb=HLT_DoubleEle17_SW_L1R_v1=
186 \item \verb=HLT_Ele17_SW_TightCaloEleId_Ele8HE_L1R_v1=
187 \item \verb=HLT_Ele17_SW_TightCaloEleId_SC8HE_L1R_v1=
188 \item \verb=HLT_DoubleEle10_SW_L1R=
189 \item \verb=HLT_DoubleEle5_SW_L1R=
190 \end{itemize}
191 \item e-$\mu$ cross triggers
192 \begin{itemize}
193 \item \verb=HLT_Mu5_Ele5_v1=
194 \item \verb=HLT_Mu5_Ele9_v1=
195 \item \verb=HLT_Mu11_Ele8_v1=
196 \item \verb=HLT_Mu8_Ele8_v1=
197 \item \verb=HLT_Mu5_Ele13_v2=
198 \item \verb=HLT_Mu5_Ele17_v1=
199 \end{itemize}
200 \end{itemize}