TOP-12-029
Study of the dependence of the top-quark mass measurement on event kinematics

Abstract

We present the first data study of possible kinematic biases in the measurement of the top-quark mass. The analysis uses a sample of tt candidate events with one electron or muon and at least four jets in the final state, collected by CMS in pp collisions at √s = 7 TeV at the LHC. A total of 5174 candidate events is selected from data corresponding to an integrated luminosity of 5.0/fb. For each event the mass is reconstructed from a kinematic fit of the decay products to a tt hypothesis. In bins of each kinematic observable the top-quark mass is determined simultaneously with the jet energy scale, constrained by the known mass of the W boson in qq decays. The effects observed are well reproduced by simulations based on MADGRAPH, POWHEG, and MC@NLO with tunes including and excluding the effects of colour reconnection.

Public Document

The document CMS-PAS-TOP-12-029 published on the CERN document server can be found here.

Figures

Categorized by anticipated sensitivity.

Colour reconnections

Figure Caption

Differential measurements as a function of the separation of the light-quark jets: (upper left) Number of permutations per bin; (upper right) top-quark mass from the 1D analysis; (lower left) JES and (lower right) top-quark mass from the 2D analysis. The systematic uncertainties are added in quadrature to the statistical uncertainties of the data. The hatched areas indicate the statistical uncertainties on the simulated samples.

PDF versions:
[Number of entries] [Top-quark mass (1D)]
[JES] [Top-quark mass (2D)]

Differential measurements as a function of the separation of the light-quark jets in phi: (upper left) Number of permutations per bin; (upper right) top-quark mass from the 1D analysis; (lower left) JES and (lower right) top-quark mass from the 2D analysis. The systematic uncertainties are added in quadrature to the statistical uncertainties of the data. The hatched areas indicate the statistical uncertainties on the simulated samples.

PDF versions:
[Number of entries] [Top-quark mass (1D)]
[JES] [Top-quark mass (2D)]

Differential measurements as a function of the transverse momentum of the hadronically decaying top quark: (upper left) Number of permutations per bin; (upper right) top-quark mass from the 1D analysis; (lower left) JES and (lower right) top-quark mass from the 2D analysis. The systematic uncertainties are added in quadrature to the statistical uncertainties of the data. The hatched areas indicate the statistical uncertainties on the simulated samples.

PDF versions:
[Number of entries] [Top-quark mass (1D)]
[JES] [Top-quark mass (2D)]

Differential measurements as a function of the pseudo-rapidity of the hadronically decaying top quark: (upper left) Number of permutations per bin; (upper right) top-quark mass from the 1D analysis; (lower left) JES and (lower right) top-quark mass from the 2D analysis. The systematic uncertainties are added in quadrature to the statistical uncertainties of the data. The hatched areas indicate the statistical uncertainties on the simulated samples.

PDF versions:
[Number of entries] [Top-quark mass (1D)]
[JES] [Top-quark mass (2D)]

Initial and final state radiation

Figure Caption

Differential measurements as a function of the HT (defined as the scalar sum of the transverse momentum of the four leading jets): (upper left) Number of permutations per bin; (upper right) top-quark mass from the 1D analysis; (lower left) JES and (lower right) top-quark mass from the 2D analysis. The systematic uncertainties are added in quadrature to the statistical uncertainties of the data. The hatched areas indicate the statistical uncertainties on the simulated samples.

PDF versions:
[Number of entries] [Top-quark mass (1D)]
[JES] [Top-quark mass (2D)]

Differential measurements as a function of the invariant mass of the ttbar system: (upper left) Number of permutations per bin; (upper right) top-quark mass from the 1D analysis; (lower left) JES and (lower right) top-quark mass from the 2D analysis. The systematic uncertainties are added in quadrature to the statistical uncertainties of the data. The hatched areas indicate the statistical uncertainties on the simulated samples.

PDF versions:
[Number of entries] [Top-quark mass (1D)]
[JES] [Top-quark mass (2D)]

Differential measurements as a function of the transverse momentum of the ttbar system: (upper left) Number of permutations per bin; (upper right) top-quark mass from the 1D analysis; (lower left) JES and (lower right) top-quark mass from the 2D analysis. The systematic uncertainties are added in quadrature to the statistical uncertainties of the data. The hatched areas indicate the statistical uncertainties on the simulated samples.

PDF versions:
[Number of entries] [Top-quark mass (1D)]
[JES] [Top-quark mass (2D)]

Differential measurements as a function of the jet multiplicity: (upper left) Number of permutations per bin; (upper right) top-quark mass from the 1D analysis; (lower left) JES and (lower right) top-quark mass from the 2D analysis. The systematic uncertainties are added in quadrature to the statistical uncertainties of the data. The hatched areas indicate the statistical uncertainties on the simulated samples.

PDF versions:
[Number of entries] [Top-quark mass (1D)]
[JES] [Top-quark mass (2D)]

b-quarks

Figure Caption

Differential measurements as a function of the transverse momentum of the b-jet assigned to the hadronic decay branch: (upper left) Number of permutations per bin; (upper right) top-quark mass from the 1D analysis; (lower left) JES and (lower right) top-quark mass from the 2D analysis. The systematic uncertainties are added in quadrature to the statistical uncertainties of the data. The hatched areas indicate the statistical uncertainties on the simulated samples.

PDF versions:
[Number of entries] [Top-quark mass (1D)]
[JES] [Top-quark mass (2D)]

Differential measurements as a function of the pseudo-rapidity of the b-jet assigned to the hadronic decay branch: (upper left) Number of permutations per bin; (upper right) top-quark mass from the 1D analysis; (lower left) JES and (lower right) top-quark mass from the 2D analysis. The systematic uncertainties are added in quadrature to the statistical uncertainties of the data. The hatched areas indicate the statistical uncertainties on the simulated samples.

PDF versions:
[Number of entries] [Top-quark mass (1D)]
[JES] [Top-quark mass (2D)]

Differential measurements as a function of the separation of the b-quark jets: (upper left) Number of permutations per bin; (upper right) top-quark mass from the 1D analysis; (lower left) JES and (lower right) top-quark mass from the 2D analysis. The systematic uncertainties are added in quadrature to the statistical uncertainties of the data. The hatched areas indicate the statistical uncertainties on the simulated samples.

PDF versions:
[Number of entries] [Top-quark mass (1D)]
[JES] [Top-quark mass (2D)]

Differential measurements as a function of the separation of the b-quark jets in phi: (upper left) Number of permutations per bin; (upper right) top-quark mass from the 1D analysis; (lower left) JES and (lower right) top-quark mass from the 2D analysis. The systematic uncertainties are added in quadrature to the statistical uncertainties of the data. The hatched areas indicate the statistical uncertainties on the simulated samples.

PDF versions:
[Number of entries] [Top-quark mass (1D)]
[JES] [Top-quark mass (2D)]
Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf diff_0_0_hadTopPt_Entries.pdf r2 r1 manage 15.0 K 2013-02-27 - 20:32 MarkusSeidel  
PNGpng diff_0_0_hadTopPt_Entries.png r2 r1 manage 35.3 K 2013-02-27 - 20:32 MarkusSeidel  
PDFpdf diff_0_1_hadTopPt_Mass.pdf r2 r1 manage 17.2 K 2013-02-27 - 20:32 MarkusSeidel  
PNGpng diff_0_1_hadTopPt_Mass.png r2 r1 manage 44.4 K 2013-02-27 - 20:32 MarkusSeidel  
PDFpdf diff_0_2_hadTopPt_MassAlt.pdf r2 r1 manage 17.4 K 2013-02-27 - 20:32 MarkusSeidel  
PNGpng diff_0_2_hadTopPt_MassAlt.png r2 r1 manage 45.4 K 2013-02-27 - 20:32 MarkusSeidel  
PDFpdf diff_0_3_hadTopPt_JES.pdf r2 r1 manage 17.3 K 2013-02-27 - 20:32 MarkusSeidel  
PNGpng diff_0_3_hadTopPt_JES.png r2 r1 manage 41.7 K 2013-02-27 - 20:32 MarkusSeidel  
PDFpdf diff_10_0_deltaPhiHadQHadQBar_Entries.pdf r2 r1 manage 16.0 K 2013-02-27 - 20:45 MarkusSeidel  
PNGpng diff_10_0_deltaPhiHadQHadQBar_Entries.png r2 r1 manage 35.8 K 2013-02-27 - 20:45 MarkusSeidel  
PDFpdf diff_10_1_deltaPhiHadQHadQBar_Mass.pdf r2 r1 manage 18.4 K 2013-02-27 - 20:45 MarkusSeidel  
PNGpng diff_10_1_deltaPhiHadQHadQBar_Mass.png r2 r1 manage 41.3 K 2013-02-27 - 20:45 MarkusSeidel  
PDFpdf diff_10_2_deltaPhiHadQHadQBar_MassAlt.pdf r2 r1 manage 18.2 K 2013-02-27 - 20:45 MarkusSeidel  
PNGpng diff_10_2_deltaPhiHadQHadQBar_MassAlt.png r2 r1 manage 38.5 K 2013-02-27 - 20:45 MarkusSeidel  
PDFpdf diff_10_3_deltaPhiHadQHadQBar_JES.pdf r2 r1 manage 18.3 K 2013-02-27 - 20:45 MarkusSeidel  
PNGpng diff_10_3_deltaPhiHadQHadQBar_JES.png r2 r1 manage 42.2 K 2013-02-27 - 20:45 MarkusSeidel  
PDFpdf diff_11_0_deltaPhiHadBLepB_Entries.pdf r2 r1 manage 16.7 K 2013-02-27 - 20:46 MarkusSeidel  
PNGpng diff_11_0_deltaPhiHadBLepB_Entries.png r2 r1 manage 38.8 K 2013-02-27 - 20:46 MarkusSeidel  
PDFpdf diff_11_1_deltaPhiHadBLepB_Mass.pdf r2 r1 manage 19.3 K 2013-02-27 - 20:46 MarkusSeidel  
PNGpng diff_11_1_deltaPhiHadBLepB_Mass.png r2 r1 manage 49.9 K 2013-02-27 - 20:46 MarkusSeidel  
PDFpdf diff_11_2_deltaPhiHadBLepB_MassAlt.pdf r2 r1 manage 19.3 K 2013-02-27 - 20:46 MarkusSeidel  
PNGpng diff_11_2_deltaPhiHadBLepB_MassAlt.png r2 r1 manage 50.3 K 2013-02-27 - 20:46 MarkusSeidel  
PDFpdf diff_11_3_deltaPhiHadBLepB_JES.pdf r2 r1 manage 19.5 K 2013-02-27 - 20:46 MarkusSeidel  
PNGpng diff_11_3_deltaPhiHadBLepB_JES.png r2 r1 manage 55.5 K 2013-02-27 - 20:46 MarkusSeidel  
PDFpdf diff_15_0_HT_Entries.pdf r2 r1 manage 14.5 K 2013-02-27 - 20:47 MarkusSeidel  
PNGpng diff_15_0_HT_Entries.png r2 r1 manage 31.2 K 2013-02-27 - 20:47 MarkusSeidel  
PDFpdf diff_15_1_HT_Mass.pdf r2 r1 manage 16.5 K 2013-02-27 - 20:47 MarkusSeidel  
PNGpng diff_15_1_HT_Mass.png r2 r1 manage 36.5 K 2013-02-27 - 20:47 MarkusSeidel  
PDFpdf diff_15_2_HT_MassAlt.pdf r2 r1 manage 16.6 K 2013-02-27 - 20:47 MarkusSeidel  
PNGpng diff_15_2_HT_MassAlt.png r2 r1 manage 34.6 K 2013-02-27 - 20:47 MarkusSeidel  
PDFpdf diff_15_3_HT_JES.pdf r2 r1 manage 17.0 K 2013-02-27 - 20:47 MarkusSeidel  
PNGpng diff_15_3_HT_JES.png r2 r1 manage 40.1 K 2013-02-27 - 20:47 MarkusSeidel  
PDFpdf diff_16_0_jetMultiplicity_Entries.pdf r2 r1 manage 13.1 K 2013-02-27 - 20:49 MarkusSeidel  
PNGpng diff_16_0_jetMultiplicity_Entries.png r2 r1 manage 27.7 K 2013-02-27 - 20:49 MarkusSeidel  
PDFpdf diff_16_1_jetMultiplicity_Mass.pdf r2 r1 manage 15.2 K 2013-02-27 - 20:49 MarkusSeidel  
PNGpng diff_16_1_jetMultiplicity_Mass.png r2 r1 manage 34.7 K 2013-02-27 - 20:49 MarkusSeidel  
PDFpdf diff_16_2_jetMultiplicity_MassAlt.pdf r2 r1 manage 15.7 K 2013-02-27 - 20:49 MarkusSeidel  
PNGpng diff_16_2_jetMultiplicity_MassAlt.png r2 r1 manage 35.9 K 2013-02-27 - 20:49 MarkusSeidel  
PDFpdf diff_16_3_jetMultiplicity_JES.pdf r2 r1 manage 15.1 K 2013-02-27 - 20:49 MarkusSeidel  
PNGpng diff_16_3_jetMultiplicity_JES.png r2 r1 manage 33.2 K 2013-02-27 - 20:49 MarkusSeidel  
PDFpdf diff_1_0_hadTopEta_Entries.pdf r2 r1 manage 16.1 K 2013-02-27 - 20:35 MarkusSeidel  
PNGpng diff_1_0_hadTopEta_Entries.png r2 r1 manage 35.3 K 2013-02-27 - 20:35 MarkusSeidel  
PDFpdf diff_1_1_hadTopEta_Mass.pdf r2 r1 manage 18.7 K 2013-02-27 - 20:35 MarkusSeidel  
PNGpng diff_1_1_hadTopEta_Mass.png r2 r1 manage 44.9 K 2013-02-27 - 20:35 MarkusSeidel  
PDFpdf diff_1_2_hadTopEta_MassAlt.pdf r2 r1 manage 18.7 K 2013-02-27 - 20:35 MarkusSeidel  
PNGpng diff_1_2_hadTopEta_MassAlt.png r2 r1 manage 47.6 K 2013-02-27 - 20:35 MarkusSeidel  
PDFpdf diff_1_3_hadTopEta_JES.pdf r2 r1 manage 18.2 K 2013-02-27 - 20:35 MarkusSeidel  
PNGpng diff_1_3_hadTopEta_JES.png r2 r1 manage 42.5 K 2013-02-27 - 20:35 MarkusSeidel  
PDFpdf diff_2_0_hadBPt_Entries.pdf r2 r1 manage 15.2 K 2013-02-27 - 20:52 MarkusSeidel  
PNGpng diff_2_0_hadBPt_Entries.png r2 r1 manage 34.5 K 2013-02-27 - 20:36 MarkusSeidel  
PDFpdf diff_2_1_hadBPt_Mass.pdf r2 r1 manage 17.3 K 2013-02-27 - 20:36 MarkusSeidel  
PNGpng diff_2_1_hadBPt_Mass.png r2 r1 manage 43.5 K 2013-02-27 - 20:36 MarkusSeidel  
PDFpdf diff_2_2_hadBPt_MassAlt.pdf r2 r1 manage 17.2 K 2013-02-27 - 20:36 MarkusSeidel  
PNGpng diff_2_2_hadBPt_MassAlt.png r2 r1 manage 40.4 K 2013-02-27 - 20:36 MarkusSeidel  
PDFpdf diff_2_3_hadBPt_JES.pdf r2 r1 manage 18.5 K 2013-02-27 - 20:36 MarkusSeidel  
PNGpng diff_2_3_hadBPt_JES.png r2 r1 manage 59.0 K 2013-02-27 - 20:36 MarkusSeidel  
PDFpdf diff_3_0_hadBEta_Entries.pdf r2 r1 manage 16.7 K 2013-02-27 - 20:37 MarkusSeidel  
PNGpng diff_3_0_hadBEta_Entries.png r2 r1 manage 33.5 K 2013-02-27 - 20:37 MarkusSeidel  
PDFpdf diff_3_1_hadBEta_Mass.pdf r2 r1 manage 20.1 K 2013-02-27 - 20:37 MarkusSeidel  
PNGpng diff_3_1_hadBEta_Mass.png r2 r1 manage 54.5 K 2013-02-27 - 20:37 MarkusSeidel  
PDFpdf diff_3_2_hadBEta_MassAlt.pdf r2 r1 manage 20.0 K 2013-02-27 - 20:37 MarkusSeidel  
PNGpng diff_3_2_hadBEta_MassAlt.png r2 r1 manage 54.9 K 2013-02-27 - 20:37 MarkusSeidel  
PDFpdf diff_3_3_hadBEta_JES.pdf r2 r1 manage 19.8 K 2013-02-27 - 20:37 MarkusSeidel  
PNGpng diff_3_3_hadBEta_JES.png r2 r1 manage 53.6 K 2013-02-27 - 20:37 MarkusSeidel  
PDFpdf diff_4_0_TTBarMass_Entries.pdf r2 r1 manage 14.5 K 2013-02-27 - 20:39 MarkusSeidel  
PNGpng diff_4_0_TTBarMass_Entries.png r2 r1 manage 30.7 K 2013-02-27 - 20:39 MarkusSeidel  
PDFpdf diff_4_1_TTBarMass_Mass.pdf r2 r1 manage 16.5 K 2013-02-27 - 20:39 MarkusSeidel  
PNGpng diff_4_1_TTBarMass_Mass.png r2 r1 manage 36.8 K 2013-02-27 - 20:39 MarkusSeidel  
PDFpdf diff_4_2_TTBarMass_MassAlt.pdf r2 r1 manage 16.6 K 2013-02-27 - 20:39 MarkusSeidel  
PNGpng diff_4_2_TTBarMass_MassAlt.png r2 r1 manage 34.7 K 2013-02-27 - 20:39 MarkusSeidel  
PDFpdf diff_4_3_TTBarMass_JES.pdf r2 r1 manage 16.8 K 2013-02-27 - 20:39 MarkusSeidel  
PNGpng diff_4_3_TTBarMass_JES.png r2 r1 manage 39.3 K 2013-02-27 - 20:39 MarkusSeidel  
PDFpdf diff_5_0_TTBarPt_Entries.pdf r2 r1 manage 14.1 K 2013-02-27 - 20:40 MarkusSeidel  
PNGpng diff_5_0_TTBarPt_Entries.png r2 r1 manage 30.7 K 2013-02-27 - 20:40 MarkusSeidel  
PDFpdf diff_5_1_TTBarPt_Mass.pdf r2 r1 manage 16.3 K 2013-02-27 - 20:40 MarkusSeidel  
PNGpng diff_5_1_TTBarPt_Mass.png r2 r1 manage 37.9 K 2013-02-27 - 20:40 MarkusSeidel  
PDFpdf diff_5_2_TTBarPt_MassAlt.pdf r2 r1 manage 16.8 K 2013-02-27 - 20:40 MarkusSeidel  
PNGpng diff_5_2_TTBarPt_MassAlt.png r2 r1 manage 39.1 K 2013-02-27 - 20:40 MarkusSeidel  
PDFpdf diff_5_3_TTBarPt_JES.pdf r2 r1 manage 16.4 K 2013-02-27 - 20:40 MarkusSeidel  
PNGpng diff_5_3_TTBarPt_JES.png r2 r1 manage 38.6 K 2013-02-27 - 20:40 MarkusSeidel  
PDFpdf diff_6_0_deltaRHadQHadQBar_Entries.pdf r2 r1 manage 15.8 K 2013-02-27 - 20:42 MarkusSeidel  
PNGpng diff_6_0_deltaRHadQHadQBar_Entries.png r2 r1 manage 34.3 K 2013-02-27 - 20:42 MarkusSeidel  
PDFpdf diff_6_1_deltaRHadQHadQBar_Mass.pdf r2 r1 manage 17.9 K 2013-02-27 - 20:42 MarkusSeidel  
PNGpng diff_6_1_deltaRHadQHadQBar_Mass.png r2 r1 manage 40.1 K 2013-02-27 - 20:42 MarkusSeidel  
PDFpdf diff_6_2_deltaRHadQHadQBar_MassAlt.pdf r2 r1 manage 18.2 K 2013-02-27 - 20:42 MarkusSeidel  
PNGpng diff_6_2_deltaRHadQHadQBar_MassAlt.png r2 r1 manage 38.6 K 2013-02-27 - 20:42 MarkusSeidel  
PDFpdf diff_6_3_deltaRHadQHadQBar_JES.pdf r2 r1 manage 18.1 K 2013-02-27 - 20:42 MarkusSeidel  
PNGpng diff_6_3_deltaRHadQHadQBar_JES.png r2 r1 manage 42.5 K 2013-02-27 - 20:42 MarkusSeidel  
PDFpdf diff_7_0_deltaRHadBLepB_Entries.pdf r2 r1 manage 16.4 K 2013-02-27 - 20:43 MarkusSeidel  
PNGpng diff_7_0_deltaRHadBLepB_Entries.png r2 r1 manage 37.3 K 2013-02-27 - 20:43 MarkusSeidel  
PDFpdf diff_7_1_deltaRHadBLepB_Mass.pdf r2 r1 manage 19.1 K 2013-02-27 - 20:43 MarkusSeidel  
PNGpng diff_7_1_deltaRHadBLepB_Mass.png r2 r1 manage 46.8 K 2013-02-27 - 20:43 MarkusSeidel  
PDFpdf diff_7_2_deltaRHadBLepB_MassAlt.pdf r2 r1 manage 19.2 K 2013-02-27 - 20:43 MarkusSeidel  
PNGpng diff_7_2_deltaRHadBLepB_MassAlt.png r2 r1 manage 48.6 K 2013-02-27 - 20:43 MarkusSeidel  
PDFpdf diff_7_3_deltaRHadBLepB_JES.pdf r2 r1 manage 18.9 K 2013-02-27 - 20:43 MarkusSeidel  
PNGpng diff_7_3_deltaRHadBLepB_JES.png r2 r1 manage 47.2 K 2013-02-27 - 20:43 MarkusSeidel  
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