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\section{Introduction} |
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\label{sec:intro} |
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In this paper we describe a search for physics beyond the standard model (BSM) |
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In this note we describe a search for physics beyond the standard model (BSM) |
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in a sample of proton-proton collisions at a centre-of-mass energy of 7~TeV. |
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The data sample was collected with the Compact Muon Solenoid (CMS) detector~\cite{JINST} at |
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the Large Hadron Collider (LHC) in 2011 |
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These cascade decays may terminate in the |
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production of weakly-interacting massive particles, resulting in large \MET. |
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The results reported in this paper are part of a broad program of BSM searches |
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The results reported in this note are part of a broad program of BSM searches |
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in events with jets and \MET, characterized by the number and |
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type of leptons in the final state. |
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Here we describe a search for events containing opposite-sign isolated |
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already been reported in Ref.~\cite{ref:RA1} {\bf ADD MORE REFS HERE}. |
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Our analysis strategy is as follows. In order to select dilepton events, we |
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use high-\pt\ dilepton triggers and a preselection based |
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use high \pt\ dilepton triggers and a preselection based |
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on that of the $t\bar{t}$ cross section measurement in the dilepton channel~\cite{ref:top}. |
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%, which used a data sample corresponding to an integrated luminosity of 3.1\pbinv. |
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Good agreement is found between this |
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above, we proceed to define 2 signal regions |
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with requirements on these quantities to select about 0.1\% |
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of dilepton $t\bar{t}$ events, as predicted by MC. |
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The observed event yields in the signal regions are compared with the predictions from two |
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We perform counting experiments in these signal regions, and compare the observed yields |
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with the predictions from two |
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independent background estimation techniques based on data control samples, |
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as well as with SM and BSM MC expectations. |
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the universal trilinear soft SUSY breaking parameter $A_0$, the |
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ratio of the vacuum expectation values of the two Higgs doublets ($\tan\beta$), and the sign of the |
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Higgs mixing parameter $\mu$. |
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Throughout the paper, two CMSSM parameter sets, referred |
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Throughout the note, two CMSSM parameter sets, referred |
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to as LM1 and LM3~\cite{TDR}, are used to illustrate possible CMSSM yields. The parameter values |
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defining LM1 (LM3) are $m_0 = 60~(330) \GeVcc$, $m_{1/2} = 250~(240) \GeVcc$, $\tan\beta = 10~(20)\GeV$; |
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both LM1 and LM3 have $A_0 = 0$ and $\mu > 0$. These two scenarios are beyond the exclusion reach |
