TOP-13-002: Combination of the CMS measurements of the mass of the top quark based on data recorded between 2010 and 2012

Status: Analysis approved during TOP PAG Meeting on September 5th, 2013

Public Document

This result supersedes the previous CMS combined measurements which were presented in TOP-11-018 and TOP-11-017 (arXiv:1307.4617). This combination uses the measurements from the 2010 run (lepton+jets, di-lepton), the four published results from the 2011 run (lepton+jets, di-lepton, all-jets, kinematic endpoints) and a preliminary result from the 2012 run (B-hadron decay length). The changes since TOP-11-017 are small and reflect an improved understanding of the categorization of some of the systematic contributions and the inclusion of additional measurements.

Abstract

Two combinations of the top quark mass from the CMS experiment are presented. These are based on data recorded between 2010 and 2012 and correspond to an integrated luminosity of up to 20 /fb. The first combination uses results obtained using standard analysis techniques in the dilepton, lepton+jets and all-jets channels. This is compared to preliminary measurements using alternative analysis techniques and to a measurement of the top quark pole mass. A second combination is performed using both the standard and alternative measurements. This results in a top quark mass of 173.49 +/- 0.36 (stat.) +/- 0.91 (syst.) GeV, with a total uncertainty of 0.98 GeV.

Results

  • 5-measurement (Standard Technique) combination

mass = 173.44 +/- 0.37 (stat.) +/- 0.91 (syst.) GeV

Chisq = 1.4 / 4 dof, Probability = 85 %

  • 7-measurement (Standard + Alternative Technique) combination

mass = 173.49 +/- 0.36 (stat.) +/- 0.91 (syst.) GeV

Chisq = 1.6 / 6 dof, Probability = 95 %

Figures

Figure Caption
Combination_5inputs.png Figure 1 - Summary of five standard CMS measurements and their combination [Get pdf version]
Comparison_5inputsalternatives.png Figure 2 - Comparison of the standard mass combination and the measurements obtained using alternative techniques. The gray band os the result of combining the five standard measurements (also shown in red). The blue points are from the alternative analyses.[Get pdf version]
Combination_7inputs.png Figure 3 - Summary of the 7 (standard+alternative) CMS measurements and their combination. [Get pdf version]

Tables

Table Caption
TOP-13-002_Table1.png Table 1 - CMS measurements and their statistical and systematic uncertainties in GeV [Get pdf version]
TOP-13-002_Table2.png Table 2 - Uncertainty category mapping for the input measurements and the result of the CMS standard measurement combination. All of the mass and uncertainty values are expressed in GeV. The terms rho_chan and rho_year are the assumed correlation factors between measurements in the same top quark decay channel and between measurements performed using data from the same year, respectively. The combination coefficients represent the contribution of each measurement to the final combination. [Get pdf version]
TOP-13-002_Table3.png Table 3 - Uncertainty category mapping for the alternative technique measurements and the result of the combination of all of the CMS mass measurements. The information for the standard measurements is shown in Table 2 and is not repeated here. All of the mass and uncertainty values are expressed in GeV. The terms rho_chan and rho_year are the assumed correlation factors between measurements in the same top quark decay channel and between measurements performed using data from the same year, respectively. The combination coefficients represent the contribution of each measurement to the final combination. The combination using the standard correlation coefficients is labelled 'CMS 2013'. The results labelled 'CMS* 2013' are shown for comparisons and are what is obtained when using limited correlatations. [Get pdf version]
TOP-13-002_Table4.png Table 4 - Combination coefficients and pulls for the measurements used in the CMS and CMS* results shown in Table 3. [Get pdf version]
TOP-13-002_Table5.png Table 5 - Correlation coefficients between the seven input measurements. [Get pdf version]

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf Combination_5inputs.pdf r1 manage 14.2 K 2013-09-13 - 21:03 StephenWimpenny CMS 5-measurement combination - Figure 1
PNGpng Combination_5inputs.png r1 manage 38.9 K 2013-09-15 - 03:18 StephenWimpenny CMS 5-measurement combination - Figure 1
PDFpdf Combination_7inputs.pdf r1 manage 14.6 K 2013-11-19 - 18:31 StephenWimpenny CMS 7-measurement combination - Figure 3
PNGpng Combination_7inputs.png r1 manage 31.2 K 2013-11-19 - 18:30 StephenWimpenny CMS 7-measurement combination - Figure 3
PDFpdf Comparison_5inputsalternatives.pdf r1 manage 13.8 K 2013-09-13 - 21:05 StephenWimpenny CMS - comparison of alternative and standard results - Figure 2
PNGpng Comparison_5inputsalternatives.png r1 manage 32.1 K 2013-09-15 - 03:27 StephenWimpenny CMS - comparison of alternative and standard results - Figure 2
PDFpdf TOP-13-002_Table1.pdf r1 manage 451.1 K 2013-09-13 - 21:27 StephenWimpenny Table 1 - Input Measutrements
PNGpng TOP-13-002_Table1.png r1 manage 102.6 K 2013-09-15 - 03:37 StephenWimpenny Table 1 - Input Measutrements
PDFpdf TOP-13-002_Table2.pdf r1 manage 2069.1 K 2013-09-13 - 21:34 StephenWimpenny Table 2 - 5-measurement combination
PNGpng TOP-13-002_Table2.png r1 manage 490.9 K 2013-09-15 - 03:38 StephenWimpenny Table 2 - 5-measurement combination
PDFpdf TOP-13-002_Table3.pdf r1 manage 1749.7 K 2013-09-13 - 21:37 StephenWimpenny Table 3 - 7-measurement combination
PNGpng TOP-13-002_Table3.png r1 manage 423.0 K 2013-09-15 - 03:38 StephenWimpenny Table 3 - 7-measurement combination
PDFpdf TOP-13-002_Table4.pdf r1 manage 578.7 K 2013-09-13 - 21:41 StephenWimpenny Table 4 - Combination coefficients
PNGpng TOP-13-002_Table4.png r1 manage 135.0 K 2013-09-15 - 03:38 StephenWimpenny Table 4 - Combination coefficients
PDFpdf TOP-13-002_Table5.pdf r1 manage 392.8 K 2013-09-13 - 21:42 StephenWimpenny Table 5 - Correlation coefficients
PNGpng TOP-13-002_Table5.png r1 manage 86.0 K 2013-09-15 - 03:39 StephenWimpenny Table 5 - Correlation coefficients
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Topic revision: r10 - 2014-03-26 - AndreasMeyer
 
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