Measurement of the Charge Asymmetry in Top Quark Pair Production

Abstract

We present a measurement of the charge asymmetry in top quark pair production using an integrated luminosity of 1.09 fb−1 collected with the CMS detector. Top quark pairs with a signature of one electron or muon and four or more jets, at least one of them b tagged, are selected. At LHC a small charge asymmetry in the rapidity distributions of top and antitop quark is predicted, with a slightly broader rapidity distribution for top quarks, while antitop quarks are produced more centrally and therefore possess a narrower rapidity distribution. We use two different sensitive variables, one based on pseudorapidities (η) of the two top quarks and one based on rapidities (y). The measured charge asymmetries of AC(η) = −0.016 0.030 (stat.)+0.010-0.019 (syst.) and AC(y) = −0.013 0.026 (stat.)+0.025-0.020(syst.) are within the uncertainties consistent with the small positive asymmetries predicted by the Standard Model.

Public document

CMS PAS TOP-11-014

Approved Results from TOP-11-014 ( click on figure to get .pdf )

Figure Description
Shapes_met_ele.eps Missing transverse energy fit templates in the electron+jets channel. PNG EPS
Shapes_met_mu.eps Missing transverse energy fit templates in the muon+jets channel. PNG EPS
Shapes_m3_ele.eps M3 fit templates in the electron+jets channel. PNG EPS
Shapes_m3_mu.eps M3 fit templates in the muon+jets channel. PNG EPS
Stack_met_ele.eps Missing transverse energy MC-data comparison in the electron+jets channel. PNG EPS
Stack_met_mu.eps Missing transverse energy MC-data comparison in the muon+jets channel. PNG EPS
Stack_m3_ele.eps M3 MC-data comparison in the electron+jets channel. PNG EPS
Stack_m3_mu.eps M3 MC-data comparison in the muon+jets channel. PNG EPS
MC_vs_Data_DeltaAbsEta_Ges.eps MC-data comparison in the ∆(abs(η)) distribution PNG EPS
MC_vs_Data_DeltaY2_Ges.eps MC-data comparison in the ∆(y^2) distribution PNG EPS
SmearingMatrix_DeltaAbsEta_Ges.eps Migration matrix between true and reconstructed distribution PNG EPS
SelectionEfficiency_DeltaAbsEta_Ges.eps Selection efficiency as function of ∆(abs(η)) PNG EPS
Result_Data_DeltaAbsEta_Ges.eps Unfolded ∆(abs(η)) distribution PNG EPS
Result_Data_DeltaY2_Ges.eps Unfolded ∆(y^2) distribution PNG EPS
DifferentialRawAsymmetry_DeltaAbsEta_Ges.eps Raw asymmetry for ∆(abs(η)) as function of invariant ttbar mass PNG EPS
DifferentialRawAsymmetry_DeltaY2_Ges.eps Raw asymmetry for ∆(y^2) as function of invariant ttbar mass PNG EPS

BGEstResultTable.jpeg Results of the BG estimation in data JPEG
SystematicTable.jpeg Table of systematic uncertainties JPEG
FinalResults.jpeg Raw, BG-subtracted and unfolded asymmetries JPEG

-- ThomasPeiffer - 18-Jul-2011

Topic attachments
I Attachment History Action Size Date Who Comment
JPEGjpeg BGEstResultTable.jpeg r1 manage 58.0 K 2011-07-20 - 09:48 ThorstenChwalek BG estimation results
Unknown file formateps DifferentialRawAsymmetry_DeltaAbsEta_Ges.eps r2 r1 manage 11.9 K 2011-07-25 - 10:48 ThorstenChwalek now quoting correct lumi
PDFpdf DifferentialRawAsymmetry_DeltaAbsEta_Ges.pdf r2 r1 manage 14.9 K 2011-07-25 - 10:48 ThorstenChwalek now quoting correct lumi
PNGpng DifferentialRawAsymmetry_DeltaAbsEta_Ges.png r2 r1 manage 17.7 K 2011-07-25 - 10:49 ThorstenChwalek now quoting correct lumi
Unknown file formateps DifferentialRawAsymmetry_DeltaY2_Ges.eps r2 r1 manage 11.9 K 2011-07-25 - 10:49 ThorstenChwalek now quoting correct lumi
PDFpdf DifferentialRawAsymmetry_DeltaY2_Ges.pdf r2 r1 manage 14.9 K 2011-07-25 - 10:49 ThorstenChwalek now quoting correct lumi
PNGpng DifferentialRawAsymmetry_DeltaY2_Ges.png r2 r1 manage 17.8 K 2011-07-25 - 10:50 ThorstenChwalek now quoting correct lumi
JPEGjpeg FinalResults.jpeg r2 r1 manage 26.5 K 2011-07-20 - 10:39 ThorstenChwalek  
Unknown file formateps MC_vs_Data_DeltaAbsEta_Ges.eps r1 manage 19.4 K 2011-07-18 - 16:12 ChristianBoeser  
PDFpdf MC_vs_Data_DeltaAbsEta_Ges.pdf r1 manage 18.1 K 2011-07-18 - 15:40 ThomasPeiffer  
PNGpng MC_vs_Data_DeltaAbsEta_Ges.png r1 manage 18.9 K 2011-07-18 - 16:12 ChristianBoeser  
Unknown file formateps MC_vs_Data_DeltaY2_Ges.eps r1 manage 20.8 K 2011-07-18 - 16:12 ChristianBoeser  
PDFpdf MC_vs_Data_DeltaY2_Ges.pdf r1 manage 18.3 K 2011-07-18 - 15:41 ThomasPeiffer  
PNGpng MC_vs_Data_DeltaY2_Ges.png r1 manage 20.9 K 2011-07-18 - 16:12 ChristianBoeser  
Unknown file formateps Result_Data_DeltaAbsEta_Ges.eps r1 manage 17.7 K 2011-07-18 - 16:13 ChristianBoeser  
PDFpdf Result_Data_DeltaAbsEta_Ges.pdf r1 manage 16.0 K 2011-07-18 - 15:41 ThomasPeiffer  
PNGpng Result_Data_DeltaAbsEta_Ges.png r1 manage 17.0 K 2011-07-18 - 16:13 ChristianBoeser  
Unknown file formateps Result_Data_DeltaY2_Ges.eps r1 manage 18.6 K 2011-07-18 - 16:13 ChristianBoeser  
PDFpdf Result_Data_DeltaY2_Ges.pdf r1 manage 16.1 K 2011-07-18 - 15:41 ThomasPeiffer  
PNGpng Result_Data_DeltaY2_Ges.png r1 manage 19.3 K 2011-07-18 - 16:13 ChristianBoeser  
Unknown file formateps SelectionEfficiency_DeltaAbsEta_Ges.eps r1 manage 9.4 K 2011-07-18 - 16:14 ChristianBoeser  
PDFpdf SelectionEfficiency_DeltaAbsEta_Ges.pdf r1 manage 14.1 K 2011-07-18 - 15:42 ThomasPeiffer  
PNGpng SelectionEfficiency_DeltaAbsEta_Ges.png r1 manage 14.9 K 2011-07-18 - 16:14 ChristianBoeser  
Unknown file formateps Shapes_m3_ele.eps r1 manage 14.6 K 2011-07-18 - 15:46 ThomasPeiffer  
PDFpdf Shapes_m3_ele.pdf r1 manage 15.2 K 2011-07-18 - 15:38 ThomasPeiffer  
PNGpng Shapes_m3_ele.png r1 manage 21.0 K 2011-07-18 - 15:46 ThomasPeiffer  
Unknown file formateps Shapes_m3_mu.eps r1 manage 14.7 K 2011-07-18 - 15:46 ThomasPeiffer  
PDFpdf Shapes_m3_mu.pdf r1 manage 15.2 K 2011-07-18 - 15:38 ThomasPeiffer  
PNGpng Shapes_m3_mu.png r1 manage 21.1 K 2011-07-18 - 15:47 ThomasPeiffer  
Unknown file formateps Shapes_met_ele.eps r1 manage 13.9 K 2011-07-18 - 15:48 ThomasPeiffer  
PDFpdf Shapes_met_ele.pdf r1 manage 15.8 K 2011-07-18 - 15:38 ThomasPeiffer  
PNGpng Shapes_met_ele.png r1 manage 19.4 K 2011-07-18 - 15:48 ThomasPeiffer  
Unknown file formateps Shapes_met_mu.eps r1 manage 16.1 K 2011-07-18 - 15:48 ThomasPeiffer  
PDFpdf Shapes_met_mu.pdf r1 manage 16.2 K 2011-07-18 - 15:39 ThomasPeiffer  
PNGpng Shapes_met_mu.png r1 manage 22.0 K 2011-07-18 - 15:48 ThomasPeiffer  
Unknown file formateps SmearingMatrix_DeltaAbsEta_Ges.eps r1 manage 12.9 K 2011-07-18 - 16:15 ChristianBoeser  
PDFpdf SmearingMatrix_DeltaAbsEta_Ges.pdf r1 manage 14.8 K 2011-07-18 - 15:42 ThomasPeiffer  
PNGpng SmearingMatrix_DeltaAbsEta_Ges.png r1 manage 15.3 K 2011-07-18 - 16:15 ChristianBoeser  
Unknown file formateps Stack_m3_ele.eps r1 manage 15.5 K 2011-07-18 - 15:49 ThomasPeiffer  
PDFpdf Stack_m3_ele.pdf r1 manage 16.0 K 2011-07-18 - 15:39 ThomasPeiffer  
PNGpng Stack_m3_ele.png r1 manage 18.3 K 2011-07-18 - 15:49 ThomasPeiffer  
Unknown file formateps Stack_m3_mu.eps r1 manage 16.3 K 2011-07-18 - 15:49 ThomasPeiffer  
PDFpdf Stack_m3_mu.pdf r1 manage 16.1 K 2011-07-18 - 15:39 ThomasPeiffer  
PNGpng Stack_m3_mu.png r1 manage 19.2 K 2011-07-18 - 15:49 ThomasPeiffer  
Unknown file formateps Stack_met_ele.eps r1 manage 18.9 K 2011-07-18 - 15:50 ThomasPeiffer  
PDFpdf Stack_met_ele.pdf r1 manage 18.2 K 2011-07-18 - 15:39 ThomasPeiffer  
PNGpng Stack_met_ele.png r1 manage 18.3 K 2011-07-18 - 15:50 ThomasPeiffer  
Unknown file formateps Stack_met_mu.eps r1 manage 19.1 K 2011-07-18 - 15:50 ThomasPeiffer  
PDFpdf Stack_met_mu.pdf r1 manage 18.3 K 2011-07-18 - 15:40 ThomasPeiffer  
PNGpng Stack_met_mu.png r1 manage 18.6 K 2011-07-18 - 15:50 ThomasPeiffer  
JPEGjpeg SystematicTable.jpeg r1 manage 84.1 K 2011-07-20 - 09:57 ThorstenChwalek  
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Topic revision: r11 - 2011-07-25 - FrankPeterSchilling
 
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