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Revision: 1.10
Committed: Thu Nov 11 12:44:58 2010 UTC (14 years, 5 months ago) by benhoob
Content type: application/x-tex
Branch: MAIN
Changes since 1.9: +4 -1 lines
Log Message:
Added stat error to ABCD prediction

File Contents

# User Rev Content
1 benhoob 1.7 \clearpage
2    
3 claudioc 1.1 \section{Results}
4     \label{sec:results}
5    
6     \begin{figure}[tbh]
7     \begin{center}
8 benhoob 1.7 \includegraphics[width=0.75\linewidth]{abcd_35pb.png}
9 claudioc 1.1 \caption{\label{fig:abcdData}\protect Distributions of SumJetPt
10     vs. MET$/\sqrt{\rm SumJetPt}$ for SM Monte Carlo and data. Here we also
11     show our choice of ABCD regions.}
12     \end{center}
13     \end{figure}
14    
15 claudioc 1.2 The data, together with SM expectations is presented
16 benhoob 1.7 in Figure~\ref{fig:abcdData}. We see 1 event in the
17     signal region (region $D$). The Standard Model MC
18     expectation is 1.4 events.
19 claudioc 1.2
20     \subsection{Background estimate from the ABCD method}
21     \label{sec:abcdres}
22    
23     The data yields in the
24     four regions are summarized in Table~\ref{tab:datayield}.
25 benhoob 1.7 The prediction of the ABCD method is is given by $A\times C/B$ and
26 benhoob 1.10 is 1.5 $\pm$ 0.9 events (statistical uncertainty only, assuming
27     Gaussian errors). (see Table~\ref{tab:datayield}).
28 claudioc 1.2
29 claudioc 1.1 \begin{table}[hbt]
30     \begin{center}
31     \caption{\label{tab:datayield} Data yields in the four
32 benhoob 1.7 regions of Figure~\ref{fig:abcdData}, as well as the predicted yield in region D given
33     by A$\times$C / B. The quoted uncertainty
34 benhoob 1.4 on the prediction in data is statistical only, assuming Gaussian errors.
35 benhoob 1.7 We also show the SM Monte Carlo expectations, scaled to 34.85~pb$^{-1}$.}
36     \begin{tabular}{l||c|c|c|c||c}
37     \hline
38     sample & A & B & C & D & A$\times$C / B \\
39     \hline
40     $t\bar{t}\rightarrow \ell^{+}\ell^{-}$ & 7.96 & 33.07 & 4.81 & 1.20 & 1.16 \\
41     $t\bar{t}\rightarrow \mathrm{other}$ & 0.15 & 0.85 & 0.09 & 0.04 & 0.02 \\
42     $Z^0$ + jets & 0.00 & 1.16 & 0.08 & 0.08 & 0.00 \\
43     $W^{\pm}$ + jets & 0.00 & 0.10 & 0.00 & 0.00 & 0.00 \\
44     $W^+W^-$ & 0.19 & 0.29 & 0.02 & 0.07 & 0.02 \\
45     $W^{\pm}Z^0$ & 0.03 & 0.04 & 0.01 & 0.01 & 0.00 \\
46     $Z^0Z^0$ & 0.00 & 0.03 & 0.00 & 0.00 & 0.00 \\
47     single top & 0.28 & 1.00 & 0.04 & 0.01 & 0.01 \\
48     \hline
49     total SM MC & 8.61 & 36.54 & 5.05 & 1.41 & 1.19 \\
50 claudioc 1.1 \hline
51 benhoob 1.7 data & 11 & 36 & 5 & 1 &1.53 $\pm$ 0.86 \\
52 claudioc 1.1 \hline
53     \end{tabular}
54     \end{center}
55     \end{table}
56    
57 claudioc 1.3 %As a cross-check, we can subtract from the yields in
58     %Table~\ref{tab:datayield} the expected DY contributions
59     %from Table~\ref{tab:ABCD-DY} in order to get a ``purer''
60     %estimate of the $t\bar{t}$ contribution. The result
61     %of this exercise is {\color{red} xx} events.
62 claudioc 1.2
63 benhoob 1.10 \clearpage
64    
65 claudioc 1.2 \subsection{Background estimate from the $P_T(\ell\ell)$ method}
66     \label{sec:victoryres}
67    
68     The number of data events in region $D'$, which is defined in
69     Section~\ref{sec:othBG} to be the same as region $D$ but with the
70     $\met/\sqrt{\rm SumJetPt}$ requirement
71     replaced by a $P_T(\ell\ell)/\sqrt{\rm SumJetPt}$ requirement
72 benhoob 1.8 is $N_{D'}=2$. Thus the BG prediction is
73 benhoob 1.6 $N_D = K \cdot K_C \cdot N_{D'} = 1.5$
74     where $K=1.5 \pm xx$ as derived in Sec.~\ref{sec:victory} and
75     $K_C = 1$.
76 claudioc 1.2 Note that if we were to subtract off from region $D'$
77 benhoob 1.8 the {\color{red} 0.8 $\pm$ 0.8} DY events estimated from
78 claudioc 1.3 Section~\ref{sec:othBG}, the background
79 benhoob 1.8 prediction would change to $N_D=1.8 \pm xx$ events.
80 benhoob 1.4
81     %%%TO BE REPLACED
82     %{\color{red}As mentioned previously, for the 11/pb analysis
83     %we use the $K$ factor from data and take $K=1$.
84     %This will change for the full dataset. We will also pay
85     %more attention to the statistical errors.}
86    
87     %The number of data events in region $D'$, which is defined in
88     %Section~\ref{sec:othBG} to be the same as region $D$ but with the
89     %$\met/\sqrt{\rm SumJetPt}$ requirement
90     %replaced by a $P_T(\ell\ell)/\sqrt{\rm SumJetPt}$ requirement
91     %is $N_{D'}=1$. Thus the BG prediction is
92     %$N_D = K \cdot K_{\rm fudge} \cdot N_{D'} = 1.5$
93     %where we used $K=1.5 \pm xx$ and $K_{\rm fudge}=1.0 \pm 0.0$.
94     %Note that if we were to subtract off from region $D'$
95     %the {\color{red} 0.4 $\pm$ 0.4} DY events estimated from
96     %Section~\ref{sec:othBG}, the background
97     %prediction would change to $N_D=0.9 \pm xx$ events.
98     %{\color{red} When we do this with a real
99     %$K_{\rm fudge}$, the fudge factor will be different
100     %after the DY subtraction.}
101 claudioc 1.1
102 claudioc 1.2 As a cross-check, we use the $P_T(\ell \ell)$
103 claudioc 1.1 method to also predict the number of events in the
104 benhoob 1.8 control region $125<{\rm SumJetPt}<300$ GeV and
105 claudioc 1.1 \met/$\sqrt{\rm SumJetPt} > 8.5$. We predict
106     $5.6^{+x}_{-y}$ events and we observe 4.
107 claudioc 1.3 The results of the $P_T(\ell\ell)$ method are
108     summarized in Figure~\ref{fig:victory}.
109 claudioc 1.1
110 claudioc 1.3 \begin{figure}[hbt]
111     \begin{center}
112 benhoob 1.8 \includegraphics[width=0.48\linewidth]{victory_control_35pb.png}
113     \includegraphics[width=0.48\linewidth]{victory_signal_35pb.png}
114 claudioc 1.3 \caption{\label{fig:victory}\protect Distributions of
115     tcMet/$\sqrt{\rm SumJetPt}$ for the control and signal region.
116     We show the oberved distributions in both Monte Carlo and data.
117     We also show the distributions predicted from
118 benhoob 1.4 ${P_T(\ell\ell)}/\sqrt{\rm SumJetPt}$ in both MC and data.}
119 claudioc 1.3 \end{center}
120     \end{figure}
121    
122    
123 benhoob 1.9 \begin{table}[hbt]
124     \begin{center}
125     \label{tab:victory_control}
126     \caption{Results of the dilepton $p_{T}$ template method in the control region
127     $125 < \mathrm{sumJetPt} < 300$~GeV. The predicted and observed yields for
128     the region $\mathrm{tcmet}/\sqrt{\mathrm{sumJetPt}}>$~8.5 are shown for data
129     and MC. The error on the prediction for data is statistical only, assuming
130     Gaussian errors.}
131     \begin{tabular}{l|c|c|c}
132     \hline
133     & Predicted & Observed & Obs/Pred \\
134     \hline
135     total SM MC & 7.10 & 8.61 & 1.21 \\
136     data & 10.38 $\pm$ 4.24 & 11 & 1.06 \\
137     \hline
138     \end{tabular}
139     \end{center}
140     \end{table}
141    
142     \begin{table}[hbt]
143     \begin{center}
144     \label{tab:victory_control}
145     \caption{Results of the dilepton $p_{T}$ template method in the signal region
146     $125 < \mathrm{sumJetPt} < 300$~GeV. The predicted and observed yields for
147     the region $\mathrm{tcmet}/\sqrt{\mathrm{sumJetPt}}>$~8.5 are shown for data
148     and MC. The error on the prediction for data is statistical only, assuming
149     Gaussian errors.}
150     \begin{tabular}{l|c|c|c}
151     \hline
152     & Predicted & Observed & Obs/Pred \\
153     \hline
154     total SM MC & 0.96 & 1.41 & 1.46 \\
155     data & 3.07 $\pm$ 2.17 & 1 & 0.33 \\
156     \hline
157     \end{tabular}
158     \end{center}
159     \end{table}
160    
161    
162 claudioc 1.3 \subsection{Summary of results}
163 claudioc 1.1 To summarize: we see no evidence for an anomalous
164     rate of opposite sign isolated dilepton events
165     at high \met and high SumJetPt. The extraction of
166     quantitative limits on new physics models is discussed
167 benhoob 1.5 in Section~\ref{sec:limit}.