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root/cvsroot/UserCode/benhoob/cmsnotes/OSPAS2011/limit.tex
Revision: 1.7
Committed: Wed Jun 15 09:14:50 2011 UTC (13 years, 11 months ago) by nmohr
Content type: application/x-tex
Branch: MAIN
Changes since 1.6: +5 -4 lines
Log Message:
New combined limit

File Contents

# User Rev Content
1 benhoob 1.1 \section{Limits on New Physics}
2     \label{sec:limit}
3    
4 benhoob 1.5 We set an upper limit on the signal yield extracted by the fit to the dilepton mass
5 benhoob 1.4 distribution, assuming the LM1 shape. The 95\% confidence level (CL) upper limit (UL)
6 nmohr 1.7 is extracted using a profile likelihood technique, giving an UL of 14.3 events, including
7     uncertainties in the background yield and shape, resolution model and $Z$ yield.
8     In the limit setting we also include the uncertainties from trigger efficiency,
9     lepton selection efficiency, hadronic energy scale and integrated luminosity on the signal efficiency.
10     The expected LM1 yield is 23 $\pm$ 3 events.
11 benhoob 1.4
12 benhoob 1.5 We set upper limits on the non-SM contributions to the high \MET\ and high \Ht\ signal regions.
13 benhoob 1.4 For both regions, we find reasonable agreement between the observed yields and the predictions from MC and from the 2
14 benhoob 1.2 data-driven methods. We choose here to extract the upper limits using the MC prediction for the
15     background estimate. The 95\% CL upper limit is extracted using a Bayesian technique~\cite{ref:cl95cms},
16 benhoob 1.6 with a log-normal model of nuissance parameter integration assuming 0 signal . The results are summarized in
17     Table~\ref{tab:results}. Based on these results, we exclude LM1 and LM3.
18 benhoob 1.1
19 benhoob 1.2 \begin{table}[hbt]
20 benhoob 1.1 \begin{center}
21 benhoob 1.2 \caption{\label{tab:results}
22 benhoob 1.5 Summary of the observed and predicted yields in the 2 signal regions. The error in the MC prediction is statistical only.
23     The systematic uncertainties on the ABCD', \ptll, and OF subtraction predictions are discussed in the text. The non-SM yield UL is a
24     Bayesian 95\% confidence level upper limit. The LM1 and LM3 yields include uncertainties from trigger efficiency,
25     lepton selection efficiency, hadronic energy scale and integrated luminosity.
26 benhoob 1.1 }
27 benhoob 1.4 \begin{tabular}{|l|c|c|c}
28 benhoob 1.2 \hline
29     & high \met\ signal region & high \Ht\ signal region \\
30     \hline
31     Observed yield & 4 & 3 \\
32     \hline
33     MC prediction & 2.6 $\pm$ 0.8 & 2.5 $\pm$ 0.8 \\
34     ABCD' prediction & 1.2 $\pm$ 0.4 (stat) $\pm$ 0.5 (syst) & 0.0 $\pm$ 0.6 (stat) $\pm$ 0.3 (syst) \\
35     \ptll\ prediction & 5.4 $\pm$ 3.8 (stat) $\pm$ 2.2 (syst) & 1.7 $\pm$ 1.7 (stat) $\pm$ 0.6 (syst) \\
36     non-SM yield UL & 5.2 & 4.1 \\
37 benhoob 1.3 LM1 yield & 17 $\pm$ 3.1 & 14 $\pm$ 3.1 \\
38 benhoob 1.6 LM3 yield & 6.4 $\pm$ 1.3 & 6.7 $\pm$ 1.6 \\
39 benhoob 1.2 \hline
40     OF subtraction ($\Delta$) & 1.3 $\pm$ 1.9 (stat) $\pm$ 0.1 (syst) & 0.1 $\pm$ 1.5 (stat) $\pm$ 0.0 (syst) \\
41     \hline
42     \end{tabular}
43 benhoob 1.1 \end{center}
44 benhoob 1.2 \end{table}