TOP-11-016

Abstract

We present a measurement of the top quark mass $m_{\rm top}$ in the dilepton decay channel $t\bar{t}\rightarrow(l^{+}\nu_l b)~(l^{-}\bar{\nu}_l \bar{b})$ in pp collisions at $\sqrt{s}=7$ TeV. The data sample of the measurement corresponds to an integrated luminosity of 2.3 fb-1 collected with the CMS detector at the LHC. Events are selected by requiring two leptons, at least two jets and missing transverse energy. The mass is reconstructed from the kinematic characteristics of the events with a full kinematic analysis. A set of templates is constructed from simulated samples and a likelihood fit is performed to derive the mass. The result yields a measurement of $m_{\rm top}=173.3\pm 1.2({\rm stat.})^{+2.5}_{-2.6} ({\rm syst.})$ GeV/c2.

Public document

The document CMS-PAS-TOP-11-016 published on the CERN document server can be found here. The Tables and Figures from the document are reproduced below. Click on the figures to retrieve the PDF version.

Tables

Table1.png
Table2.png

Figures

Figure Caption
Top quark mass solutions for the KINb method for the two lepton-jet combinations after smearing the jet energy resolution for one selected event in data. The combination #2 is chosen in this case; the solid red line corresponds to the Gaussian fit used to estimate $m_{\rm KINb}$.
Results of the fit for same (different) flavour dileptons are shown on top (bottom) for events with one (left) or at least two b-tags (right). Also shown are the total background plus signal model and the background-only shape (shaded).
Variation of the likelihood used to extract the top quark mass, in the different event categories and for all channels combined.
(Top) Fitted top quark mass values using the KINb algorithm from simulated pseudo-experiments, including signal and background processes, as a function of the actual top quark mass used in the simulation. A linear fit to the points is also shown. (Bottom) The difference (bias) between the linear fit and the actual reconstructed values from the pseudo-experiments. The bias is shown after calibrating the signal parametrization.

Supporting figures

The figures shown below are meant for more detailed illustration of our analysis.

Kinematic distributions for event selection

Figure Caption

Top mass reconstruction with the KINb method

Figure Caption

-- PedroSilva - 23-Feb-2012

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Topic attachments
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PDFpdf 163402352376774543.pdf r1 manage 15.7 K 2012-02-23 - 17:35 PedroSilva  
PNGpng 163402352376774543.png r1 manage 17.0 K 2012-02-23 - 18:01 PedroSilva  
PDFpdf DYPDF_of.pdf r1 manage 20.3 K 2012-02-24 - 12:08 PietroVischia  
PNGpng DYPDF_of.png r1 manage 27.4 K 2012-02-24 - 12:08 PietroVischia  
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PDFpdf MassFitLikelihood_exclusive.pdf r1 manage 18.2 K 2012-02-23 - 17:42 PedroSilva  
PNGpng MassFitLikelihood_exclusive.png r1 manage 21.7 K 2012-02-23 - 17:42 PedroSilva  
PDFpdf MassFitResults_exclusive.pdf r1 manage 31.8 K 2012-02-23 - 17:35 PedroSilva  
PNGpng MassFitResults_exclusive.png r1 manage 64.1 K 2012-02-23 - 17:34 PedroSilva  
PDFpdf NonDYPDF.pdf r1 manage 20.7 K 2012-02-24 - 12:05 PietroVischia  
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PDFpdf SignalPDF__1btags.pdf r1 manage 49.9 K 2012-02-24 - 12:02 PietroVischia  
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PNGpng SignalPDF_of_2btags.png r1 manage 136.3 K 2012-02-24 - 12:03 PietroVischia  
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PNGpng Table1.png r1 manage 115.2 K 2012-02-23 - 17:58 PedroSilva  
PNGpng Table2.png r2 r1 manage 54.7 K 2012-02-23 - 23:10 PedroSilva  
PDFpdf TopMassCalibrationResults_exclusive_final.pdf r1 manage 15.5 K 2012-02-23 - 17:25 PedroSilva  
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PDFpdf alleq0btags_mtop.pdf r1 manage 22.5 K 2012-02-24 - 11:57 PietroVischia  
PNGpng alleq0btags_mtop.png r1 manage 26.8 K 2012-02-24 - 11:57 PietroVischia  
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