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Revision: 1.7
Committed: Fri Nov 5 15:53:20 2010 UTC (14 years, 6 months ago) by claudioc
Content type: application/x-tex
Branch: MAIN
Changes since 1.6: +5 -1 lines
Log Message:
typo fixed, new dpt cit on muons

File Contents

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