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Revision: 1.6
Committed: Thu Nov 4 04:14:21 2010 UTC (14 years, 6 months ago) by claudioc
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Changes since 1.5: +4 -2 lines
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# User Rev Content
1 claudioc 1.1 \section{Event Preselection}
2     \label{sec:eventSel}
3 claudioc 1.6 %{\color{red} This needs to be fixed up -- probably many mistakes present.}\\
4 claudioc 1.1 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 claudioc 1.5 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 claudioc 1.6 (we use tcMet). More details are given in the subsections below.
17 claudioc 1.1
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 claudioc 1.3 \item $|z| < 24$ cm.
29 claudioc 1.1 \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 claudioc 1.5 \item $|\eta| < 2.4$.
41 claudioc 1.1
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 claudioc 1.6 \item {\color{red} Should we add a cut on the momentum error?}
59    
60 claudioc 1.1 \end{itemize}
61    
62    
63    
64 claudioc 1.2 \subsection{Electron Selection}
65 claudioc 1.1 \label{sec:electron}
66    
67     Electron candidates are RECO GSF electrons passing the following
68     requirements:
69    
70     \begin{itemize}
71    
72     \item $P_T > 10$ GeV. (The $t\bar{t}$ analysis uses 20 GeV but for
73     completeness we calculate FR down to 10 GeV).
74    
75     \item $|\eta| < 2.5$.
76    
77     \item SuperCluster $E_T > 10$ GeV.
78    
79     \item The electron must be ecal seeded.
80    
81     \item VBTF90 identification\cite{ref:vbtf}.
82    
83     \item Transverse impact parameter with respect to the beamspot $<$ 400 $\mu$m.
84    
85     \item $Iso \equiv $ $E_T^{\rm iso}$/Max(20 GeV, $P_T$) $<$ 0.15.
86     $E_T^{\rm iso}$
87     is defined as the sum of transverse energy/momentum deposits in ecal,
88     hcal, and tracker, in a
89     cone of 0.3. A 1 GeV pedestal is subtracted from the ecal energy
90     deposition in the EB, however the ecal energy is never allowed to
91     go negative.
92    
93     \item Electrons with a tracker or global muon within $\Delta R$ of
94     0.1 are vetoed.
95    
96     \item The number of missing expected inner hits must be less than
97     two\cite{ref:conv}.
98    
99     \item Conversion removal via partner track finding: any electron
100     where an additional GeneralTrack is found with $Dist < 0.02$ cm
101     and $\Delta \cot \theta < 0.02$ is vetoed\cite{ref:conv}.
102    
103 claudioc 1.4 \item Cleaning for ECAL spike (aka Swiss-Cross cleaning) has been applied
104     at the reconstruction level (CMSSW 38x).
105 claudioc 1.1
106     \end{itemize}
107    
108 claudioc 1.5 \subsection{Invariant mass requirement}
109 claudioc 1.2 \label{sec:zveto}
110    
111     We remove $e^+e^-$ and $\mu^+ \mu^-$ events with invariant
112 claudioc 1.5 mass between 76 and 106 GeV. We also remove events
113     with invariant mass $<$ 10 GeV.
114 claudioc 1.2
115     \subsection{Trigger Selection}
116 claudioc 1.1 \label{sec:trigSel}
117    
118     Because most of the triggers implemented in the 2nd half of the
119     2010 run were not implemented in the Monte Carlo, no trigger
120     selection is applied on Monte Carlo data. As discussed in
121     Section~\ref{sec:trgEff}, a trigger efficiency weight is applied
122     to each event, based on the trigger efficiencies measured on data.
123     Trigger efficiency weights are very close to 1.
124    
125 claudioc 1.5 %For data, we require the logical OR of all (or most?) unprescaled
126     %single and double lepton triggers that were deployed during the 2010
127     %run. These are:
128     %{\color{red} Here we need to list the triggers, somehow.}
129    
130     For data, we use a cocktail of unprescaled single
131     and double lepton triggers. An event
132     in the $ee$ final state is required to pass at least 1
133     single- or double-electron trigger, a
134     $\mu\mu$ event is required to pass at least 1 single
135     or double-muon trigger, while an $e\mu$ event
136     is required to pass at least 1 single-muon, single-electron,
137     or $e-\mu$ cross trigger.
138     % We currently
139     % do not require MC events to pass any triggers.
140 claudioc 1.1
141 claudioc 1.5 \begin{itemize}
142     \item single-muon triggers
143     \begin{itemize}
144     \item \verb=HLT_Mu5=
145     \item \verb=HLT_Mu7=
146     \item \verb=HLT_Mu9=
147     \item \verb=HLT_Mu11=
148     \item \verb=HLT_Mu13_v1=
149     \item \verb=HLT_Mu15_v1=
150     \item \verb=HLT_Mu17_v1=
151     \item \verb=HLT_Mu19_v1=
152     \end{itemize}
153     \item double-muon triggers
154     \begin{itemize}
155     \item \verb=HLT_DoubleMu3=
156     \item \verb=HLT_DoubleMu3_v2=
157     \item \verb=HLT_DoubleMu5_v1=
158     \end{itemize}
159     \item single-electron triggers
160     \begin{itemize}
161     \item \verb=HLT_Ele10_SW_EleId_L1R=
162     \item \verb=HLT_Ele10_LW_EleId_L1R=
163     \item \verb=HLT_Ele10_LW_L1R=
164     \item \verb=HLT_Ele10_SW_L1R=
165     \item \verb=HLT_Ele15_SW_CaloEleId_L1R=
166     \item \verb=HLT_Ele15_SW_EleId_L1R=
167     \item \verb=HLT_Ele15_SW_L1R=
168     \item \verb=HLT_Ele15_LW_L1R=
169     \item \verb=HLT_Ele17_SW_TightEleId_L1R=
170     \item \verb=HLT_Ele17_SW_TighterEleId_L1R_v1=
171     \item \verb=HLT_Ele17_SW_CaloEleId_L1R=
172     \item \verb=HLT_Ele17_SW_EleId_L1R=
173     \item \verb=HLT_Ele17_SW_LooseEleId_L1R=
174     \item \verb=HLT_Ele17_SW_TighterEleIdIsol_L1R_v2=
175     \item \verb=HLT_Ele20_SW_L1R=
176     \item \verb=HLT_Ele22_SW_TighterEleId_L1R_v2=
177     \item \verb=HLT_Ele32_SW_TightCaloEleIdTrack_L1R_v1=
178     \item \verb=HLT_Ele32_SW_TighterEleId_L1R_v2=
179     \item \verb=HLT_Ele27_SW_TightCaloEleIdTrack_L1R_v1=
180     \item \verb=HLT_Ele22_SW_TighterCaloIdIsol_L1R_v2=
181     \item \verb=HLT_Ele22_SW_TighterEleId_L1R_v3=
182     \item \verb=HLT_Ele22_SW_TighterCaloIdIsol_L1R_v2=
183     \end{itemize}
184     \item double-electron triggers
185     \begin{itemize}
186     \item \verb=HLT_DoubleEle15_SW_L1R_v1=
187     \item \verb=HLT_DoubleEle17_SW_L1R_v1=
188     \item \verb=HLT_Ele17_SW_TightCaloEleId_Ele8HE_L1R_v1=
189     \item \verb=HLT_Ele17_SW_TightCaloEleId_SC8HE_L1R_v1=
190     \item \verb=HLT_DoubleEle10_SW_L1R=
191     \item \verb=HLT_DoubleEle5_SW_L1R=
192     \end{itemize}
193     \item e-$\mu$ cross triggers
194     \begin{itemize}
195     \item \verb=HLT_Mu5_Ele5_v1=
196     \item \verb=HLT_Mu5_Ele9_v1=
197     \item \verb=HLT_Mu11_Ele8_v1=
198     \item \verb=HLT_Mu8_Ele8_v1=
199     \item \verb=HLT_Mu5_Ele13_v2=
200     \item \verb=HLT_Mu5_Ele17_v1=
201     \end{itemize}
202     \end{itemize}