Search for Resonances in Semi-leptonic Top-pair Decays Close to Production Threshold

Link to TOP-10-007 PAS in CDS

Abstract

We present the results of a search for massive neutral bosons decaying via a top-antitop quark pair. The analysis is based on 36 pb-1 of proton-proton collision data at a centre-of-mass energy of 7 TeV collected by the CMS detector at the LHC during 2010. From a combined analysis of the muon plus jets and electron plus jets decay modes no significant signal is observed, and upper limits on the production cross section as a function of the boson mass are reported.

Approved Plots from TOP-10-007 ( click on plot to get .pdf )

Figure Abbreviated Caption
resolution_chi2_mujets.pdf Resolution of reconstructed m(ttbar) as a function of generated m(ttbar) for muon plus jets events GIF
resolution_chi2_ejets.pdf Resolution of reconstructed m(ttbar) as a function of generated m(ttbar) for electron plus jets events GIF
kinematics_2jetsw_both__sumEt.pdf Comparison of the QCD background shapes in the muon channel, showing the distribution of the scalar sum of pt in events with exactly two jets GIF
kinematics_3jetsw_both__mttbar3jets.pdf Comparison of the QCD background shapes in the muon channel, showing the distribution of m(ttbar) in events with exactly three jets GIF
muon_mttbar_3jets_chi2_3j1t_max.pdf Reconstructed m(ttbar) using leading 3 jets (3-jet events with at least one b tag) in the muon + jets channel GIF
muon_mttbar_fit_chi2btags_4j0t_max.pdf Reconstructed m(ttbar) after kinematic fit (4-jet events with 0 b tags) in the muon + jets channel GIF
muon_mttbar_fit_chi2btags_4j1t_max.pdf Reconstructed m(ttbar) after kinematic fit (4-jet events with 1 b tag) in the muon + jets channel GIF
muon_mttbar_fit_chi2btags_4j2t_max.pdf Reconstructed m(ttbar) after kinematic fit (4-jet events with at least 2 b tags) in the muon + jets channel GIF
electron_mttbar_3jets_chi2_3j1t_max.pdf Reconstructed m(ttbar) using leading 3 jets (3-jet events with at least one b tag) in the electron + jets channel GIF
electron_mttbar_fit_chi2btags_4j0t_max.pdf Reconstructed m(ttbar) after kinematic fit (4-jet events with 0 b tags) in the electron + jets channel GIF
electron_mttbar_fit_chi2btags_4j1t_max.pdf Reconstructed m(ttbar) after kinematic fit (4-jet events with 1 b tag) in the electron + jets channel GIF
electron_mttbar_fit_chi2btags_4j2t_max.pdf Reconstructed m(ttbar) after kinematic fit (4-jet events with at least 2 b tags) in the electron + jets channel GIF
limits_mcmc95_lognormal.pdf Expected and observed limits from Bayesian integration using Markov chain Monte Carlo for σ(pp → Z') x BR(Z' → t tbar ) for 36 pb-1 of data as a function of Z' mass. GIF
combined_mttbar_3jets_chi2_3j1t_max.pdf Reconstructed m(ttbar) using leading 3 jets in 3-jet events with at least one b tag in electron and muon channels combined (for illustration purposes only). GIF
combined_mttbar_fit_chi2btags_4j_max.pdf Reconstructed m(ttbar) in all 4 or more-jet events in electron and muon channels combined (for illustration purposes only). GIF

Cross check analysis

Mtt_2btag_mu.pdf Reconstructed m(ttbar) in data for 36 pb-1 of luminosity for the control-check analysis, for the muon channel. The data are compared with the expectations of the SM, divided into the various components GIF
Mtt_2btag_e.pdf Reconstructed m(ttbar) in data for 36 pb-1 of luminosity for the control-check analysis, for the electron channel. The data are compared with the expectations of the SM, divided into the various components GIF

-- SilvanoTosi - 11-Mar-2011

Topic attachments
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GIFgif Mtt_2btag_e.gif r1 manage 98.6 K 2011-03-11 - 12:16 SilvanoTosi  
PDFpdf Mtt_2btag_e.pdf r1 manage 58.0 K 2011-03-11 - 12:16 SilvanoTosi  
GIFgif Mtt_2btag_mu.gif r1 manage 100.3 K 2011-03-11 - 12:16 SilvanoTosi  
PDFpdf Mtt_2btag_mu.pdf r1 manage 59.0 K 2011-03-11 - 12:16 SilvanoTosi  
GIFgif combined_mttbar_3jets_chi2_3j1t_max.gif r1 manage 55.7 K 2011-03-14 - 17:44 SilvanoTosi  
PDFpdf combined_mttbar_3jets_chi2_3j1t_max.pdf r1 manage 19.1 K 2011-03-14 - 17:44 SilvanoTosi  
GIFgif combined_mttbar_fit_chi2btags_4j_max.gif r1 manage 55.0 K 2011-03-14 - 17:44 SilvanoTosi  
PDFpdf combined_mttbar_fit_chi2btags_4j_max.pdf r1 manage 19.6 K 2011-03-14 - 17:44 SilvanoTosi  
GIFgif electron_mttbar_3jets_chi2_3j1t_max.gif r1 manage 58.1 K 2011-03-11 - 12:01 SilvanoTosi  
PDFpdf electron_mttbar_3jets_chi2_3j1t_max.pdf r1 manage 19.8 K 2011-03-11 - 12:01 SilvanoTosi  
GIFgif electron_mttbar_fit_chi2btags_4j0t_max.gif r1 manage 56.5 K 2011-03-11 - 12:01 SilvanoTosi  
PDFpdf electron_mttbar_fit_chi2btags_4j0t_max.pdf r1 manage 19.0 K 2011-03-11 - 12:01 SilvanoTosi  
GIFgif electron_mttbar_fit_chi2btags_4j1t_max.gif r1 manage 54.0 K 2011-03-11 - 12:01 SilvanoTosi  
PDFpdf electron_mttbar_fit_chi2btags_4j1t_max.pdf r1 manage 18.9 K 2011-03-11 - 12:02 SilvanoTosi  
GIFgif electron_mttbar_fit_chi2btags_4j2t_max.gif r1 manage 52.9 K 2011-03-11 - 12:02 SilvanoTosi  
PDFpdf electron_mttbar_fit_chi2btags_4j2t_max.pdf r1 manage 19.4 K 2011-03-11 - 12:02 SilvanoTosi  
GIFgif kinematics_2jetsw_both__sumEt.gif r2 r1 manage 51.3 K 2011-03-14 - 17:20 SilvanoTosi  
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GIFgif kinematics_3jetsw_both__mttbar3jets.gif r2 r1 manage 55.8 K 2011-03-14 - 17:20 SilvanoTosi  
PDFpdf kinematics_3jetsw_both__mttbar3jets.pdf r2 r1 manage 16.6 K 2011-03-14 - 17:20 SilvanoTosi  
GIFgif limits_mcmc95_lognormal.gif r1 manage 52.5 K 2011-03-11 - 12:08 SilvanoTosi  
PDFpdf limits_mcmc95_lognormal.pdf r1 manage 15.2 K 2011-03-11 - 12:08 SilvanoTosi  
GIFgif muon_mttbar_3jets_chi2_3j1t_max.gif r1 manage 54.3 K 2011-03-11 - 12:02 SilvanoTosi  
PDFpdf muon_mttbar_3jets_chi2_3j1t_max.pdf r1 manage 19.3 K 2011-03-11 - 12:02 SilvanoTosi  
GIFgif muon_mttbar_fit_chi2btags_4j0t_max.gif r1 manage 57.1 K 2011-03-11 - 12:02 SilvanoTosi  
PDFpdf muon_mttbar_fit_chi2btags_4j0t_max.pdf r1 manage 19.1 K 2011-03-11 - 12:03 SilvanoTosi  
GIFgif muon_mttbar_fit_chi2btags_4j1t_max.gif r1 manage 54.2 K 2011-03-11 - 12:03 SilvanoTosi  
PDFpdf muon_mttbar_fit_chi2btags_4j1t_max.pdf r1 manage 19.7 K 2011-03-11 - 12:03 SilvanoTosi  
GIFgif muon_mttbar_fit_chi2btags_4j2t_max.gif r1 manage 55.7 K 2011-03-11 - 12:03 SilvanoTosi  
PDFpdf muon_mttbar_fit_chi2btags_4j2t_max.pdf r1 manage 19.3 K 2011-03-11 - 12:03 SilvanoTosi  
GIFgif resolution_chi2_ejets.gif r3 r2 r1 manage 13.3 K 2011-03-14 - 13:51 SilvanoTosi  
PDFpdf resolution_chi2_ejets.pdf r2 r1 manage 15.5 K 2011-03-14 - 13:51 SilvanoTosi  
GIFgif resolution_chi2_mujets.gif r3 r2 r1 manage 13.4 K 2011-03-14 - 13:51 SilvanoTosi  
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