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Revision: 1.10
Committed: Mon Nov 8 10:27:26 2010 UTC (14 years, 6 months ago) by benhoob
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Branch: MAIN
CVS Tags: nov8th_official
Changes since 1.9: +9 -8 lines
Log Message:
Put footnote about multi-lepton events into body of text, remove reference to generalized lepton veto

File Contents

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