Search for supersymmetry in all-hadronic events with missing energy

Abstract

A search for new physics is presented based on an event signature of at least three jets accompanied by large missing transverse momentum, using a data sample corresponding to an integrated luminosity of 1.1 / fb collected in proton–proton collisions at √s = 7 TeV with the CMS detector at the LHC. No excess of events is observed above the expected standard model backgrounds, which are all estimated from the data. Exclusion limits are presented for the constrained minimal supersymmetric extension of the standard model.

Plots from PAS-SUS-11-004 (Click on plot to get .pdf)

Figure Caption
Figure 1: HT, MHT, and effective mass (defined as sum of HT and MHT) distributions for the data and MC simulation samples with all baseline selection cuts applied.
 
Figure 2: HT and MHT distributions after baseline selection for photon data and MC.
Figure 3: The closure test of the method for the lost-lepton background prediction. The lost-lepton background prediction obtained from MC simulated events using the data-driven method compared to MC ttbar and W+jets expectation. The uncertainty band relates to the total statistical uncertainty of the prediction, i.e. from the control sample and the efficiency measurement. The systematic uncertainties are not included. The shown variables are HT (top left), MHT (top right), and the number of primary vertices (bottom). The ratio of the data-driven prediction from MC to the MC expectation is also shown.
 
Figure 4: Predictions of the lost-lepton background using muon control sample from data for HT (left) and MHT (right) compared to MC ttbar and W+jets expectation. The ratio of the prediction from data to the MC expectation is also shown.
Figure 5: The closure test of the method for the hadronic-tau background prediction. HT (left) and MHT (right) distributions predicted from simulated events using the data-driven method compared to the MC expectation of the hadronic-tau background for the baseline selection. Uncertainties are statistical only. The fractional difference of the data-driven prediction from simulated events with respect to the MC expectation is also shown.
Figure 6: R+S prediction compared to fully simulated MC distributions. Top left: HT distribution for events passing ≥ 3 jets; top right: MHT distribution for events passing ≥ 3 jets and HT ≥ 350 GeV; bottom: MHT distribution for events passing ≥ 3 jets, HT ≥ 350 GeV, and ΔΦ(MHT,jet1-3).
Figure 7: (Left) The jet pt resolution as a function of the threshold on pT,3 / pTave for one example bin in pTave and η. The results from simulation (open squares) are overlaid with the measurement from data (solid circles). They are fitted with a straight line to extrapolate to zero additional jet activity. (Right) Ratio of the extrapolated resolution measured in data and simulation in the central η bin as a function of pT. The correction factor is obtained by fitting a constant.
Figure 8: (Left) Example dijet asymmetry distribution for data (solid circles) compared to the Monte Carlo simulation (filled histogram). The latter has been corrected for the measured core resolution differences. The area beyond asymmetries of 0.1, indicated by the arrow, defines the tail region. For comparison, the hatched area shows number of events expected for a purely Gaussian response. (Right) Ratios of the fractional number of tail events in data and MC simulation in bins of ptave for the central eta region. They were used as scale factors for the tails of the MC truth response distribution.
Figure 9: HT and MHT distributions in data compared to the combined data-driven background predictions. The ratio of data to the combined data-driven background predictions is also shown. While the integrated background uncertainty corresponds to the values listed in Tab. 10, the bin-by-bin combination of the background contributions and their uncertainties has been performed in a simplified way assuming Gaussian probability distributions.
  Figure 10: The observed and expected 95% CL exclusion contours in the CMSSM parameter m0-m1/2 plane using the signal cross sections calculated at NLO. The shown contours are the combination of the different selections, such that the shown contours are the envelope with respect to best sensitivity. The remaining CMSSM parameters are tan(β) = 10, μ > 0, and A0 = 0. The limits from the earlier CMS searches and from other experiments are also shown.
combined_Exclusion_m0_m12_tb10_OnlyRA2LimitCurves.C   Script containing the list of points corresponding to the observed and expected limit contours in (m0, m1/2) plane as shown in figure 10. Also listed are the points for one sigma band around the expected limit contour.

Figure 11: The efficiency for the baseline selection (HT>350 GeV, MHT>200 GeV) in the CMSSM (m0, m1/2) plane with tan(β) = 10, μ > 0, and A0 = 0. The white cells correspond to unavailable samples. The actual efficiency values can be found here.
Figure 12: The efficiency for the high MHT selection (HT>800 GeV, MHT>500 GeV) in the CMSSM (m0, m1/2) plane with tan(β) = 10, μ > 0, and A0 = 0. The white cells correspond to unavailable samples. The actual efficiency values can be found here.
Figure 13: The efficiency for the high HT selection (HT>800 GeV, MHT>200 GeV) in the CMSSM (m0, m1/2) plane with tan(β) = 10, μ > 0, and A0 = 0. The white cells correspond to unavailable samples. The actual efficiency values can be found here.

Re-interpretation in terms of simplified models

The language of simplified models has been introduced recently (see e.g. here and here) to establish an efficient communication channel between the LHC experiments and the theory communities who have proposed a general set of simplified models with which LHC data can be interpreted. A similar approach has been taken before in the hadronic channel with 2010 data -- see here.

The above results have been re-interpreted in terms of the simplified models given in the following table. The signal efficiencies as a function of the mass parameters of the simplified model are also given below, together with upper limit plots on the production cross section. More than one search selection are present and the selection that has the best expected upper limit is used. The data for these plots are also available as a ROOT file T1_T2_T5zz_RA2.root . The regions with small 
ΔΜ(gluino,LSP)
 and
 low gluino 
mass
 are 
excluded since they are
 dominated by 
statistical 
errors 
and
 signal 
modeling uncertainty. Signal contamination in control regions has not been taken into account when computing the upper limits on the production cross sections.

Simplified model topology name Simplified model topology Best Selection Limit Caption
"T1" T1.png h_selRA2_T1_best.png h_limitRA2_T1_best.png Upper limit on production cross section, for T1, assuming a branching ratio of 1. Superimposed are 95% CL exclusion contours, assuming a "reference SUSY cross section", for decoupled squarks: m(~q)>>m(~g).
"T2" T2.png h_selRA2_T2_best.png h_limitRA2_T2_best.png Upper limit on production cross section, for T2, assuming a branching ratio of 1. Superimposed are 95% CL exclusion contours, assuming a "reference SUSY cross section", for decoupled gluino: m(~g)>>m(~q).
"T5zz" T5zz.png h_selRA2_T5zz_best.png h_limitRA2_T5zz_best.png Upper limit on production cross section, for T5zz, assuming a branching ratio of 1. Superimposed are 95% CL exclusion contours, assuming a "reference SUSY cross section", for decoupled squarks: m(~q)>>m(~g).

-- MatthiasSchroederHH - 28-Aug-2011

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf Closure_HT.pdf r1 manage 8.6 K 2011-08-28 - 22:41 MatthiasSchroederHH  
PNGpng Closure_HT.png r1 manage 24.6 K 2011-08-28 - 22:41 MatthiasSchroederHH  
PDFpdf Closure_MHT.pdf r1 manage 8.3 K 2011-08-28 - 22:42 MatthiasSchroederHH  
PNGpng Closure_MHT.png r1 manage 24.1 K 2011-08-28 - 22:42 MatthiasSchroederHH  
PDFpdf Closure_NVertex.pdf r1 manage 6.9 K 2011-08-28 - 22:42 MatthiasSchroederHH  
PNGpng Closure_NVertex.png r1 manage 20.5 K 2011-08-28 - 22:42 MatthiasSchroederHH  
PDFpdf Final_HT.pdf r1 manage 8.1 K 2011-08-28 - 22:44 MatthiasSchroederHH  
PNGpng Final_HT.png r1 manage 23.3 K 2011-08-28 - 22:44 MatthiasSchroederHH  
PDFpdf Final_MHT.pdf r1 manage 8.1 K 2011-08-28 - 22:44 MatthiasSchroederHH  
PNGpng Final_MHT.png r1 manage 23.2 K 2011-08-28 - 22:44 MatthiasSchroederHH  
PDFpdf QCD_SmearingClosure_OnMC_LowHT_MHT.pdf r1 manage 17.1 K 2011-08-28 - 22:44 MatthiasSchroederHH  
PNGpng QCD_SmearingClosure_OnMC_LowHT_MHT.png r1 manage 26.9 K 2011-08-28 - 22:44 MatthiasSchroederHH  
PDFpdf QCD_SmearingClosure_OnMC_LowNoDeltaPhi_MHT.pdf r1 manage 17.2 K 2011-08-28 - 22:45 MatthiasSchroederHH  
PNGpng QCD_SmearingClosure_OnMC_LowNoDeltaPhi_MHT.png r1 manage 26.8 K 2011-08-28 - 22:45 MatthiasSchroederHH  
PDFpdf QCD_SmearingClosure_OnMC_PreSelection_HT.pdf r1 manage 18.9 K 2011-08-28 - 22:45 MatthiasSchroederHH  
PNGpng QCD_SmearingClosure_OnMC_PreSelection_HT.png r1 manage 31.0 K 2011-08-28 - 22:45 MatthiasSchroederHH  
PDFpdf RA2DataVsEstimatedBkg_HT.pdf r1 manage 14.0 K 2011-08-28 - 22:45 MatthiasSchroederHH  
PNGpng RA2DataVsEstimatedBkg_HT.png r1 manage 15.9 K 2011-08-28 - 22:46 MatthiasSchroederHH  
PDFpdf RA2DataVsEstimatedBkg_MHT.pdf r1 manage 14.4 K 2011-08-28 - 22:46 MatthiasSchroederHH  
PNGpng RA2DataVsEstimatedBkg_MHT.png r1 manage 16.5 K 2011-08-28 - 22:46 MatthiasSchroederHH  
PDFpdf Res_163337-167151_PF_Extrapolation_AllSamples_EtaBin0_PtBin3.pdf r1 manage 7.9 K 2011-08-28 - 22:46 MatthiasSchroederHH  
PNGpng Res_163337-167151_PF_Extrapolation_AllSamples_EtaBin0_PtBin3.png r1 manage 33.2 K 2011-08-28 - 22:46 MatthiasSchroederHH  
PDFpdf Res_163337-167151_PF_ResolutionRatio_Data_vs_CMSSimulation_EtaBin0.pdf r1 manage 11.5 K 2011-08-28 - 22:47 MatthiasSchroederHH  
PNGpng Res_163337-167151_PF_ResolutionRatio_Data_vs_CMSSimulation_EtaBin0.png r1 manage 29.4 K 2011-08-28 - 22:47 MatthiasSchroederHH  
PNGpng T1.png r1 manage 19.8 K 2011-11-18 - 21:27 MariarosariaDalfonso  
PNGpng T2.png r1 manage 15.4 K 2011-11-18 - 21:28 MariarosariaDalfonso  
PDFpdf T5zz.pdf r1 manage 10.2 K 2011-11-18 - 21:29 MariarosariaDalfonso  
PNGpng T5zz.png r1 manage 18.9 K 2011-11-18 - 21:28 MariarosariaDalfonso  
PDFpdf Tail_163337-167151_Sig25-Inf_PF_EtaBin0_PtBin3_Pt3Bin2_PtSmearAsymTail.pdf r1 manage 16.4 K 2011-08-28 - 22:47 MatthiasSchroederHH  
PNGpng Tail_163337-167151_Sig25-Inf_PF_EtaBin0_PtBin3_Pt3Bin2_PtSmearAsymTail.png r1 manage 38.0 K 2011-08-28 - 22:47 MatthiasSchroederHH  
PDFpdf Tail_163337-167151_Sig25-Inf_PF_ScaleFactors_Eta0.pdf r1 manage 10.4 K 2011-08-28 - 22:48 MatthiasSchroederHH  
PNGpng Tail_163337-167151_Sig25-Inf_PF_ScaleFactors_Eta0.png r1 manage 22.3 K 2011-08-28 - 22:48 MatthiasSchroederHH  
PDFpdf c_h_RA2_HT_DataMC_Scaled.pdf r1 manage 5.9 K 2011-08-28 - 22:39 MatthiasSchroederHH  
PNGpng c_h_RA2_HT_DataMC_Scaled.png r1 manage 14.2 K 2011-08-28 - 22:39 MatthiasSchroederHH  
PDFpdf c_h_RA2_MHT_DataMC_Scaled.pdf r1 manage 7.2 K 2011-08-28 - 22:39 MatthiasSchroederHH  
PNGpng c_h_RA2_MHT_DataMC_Scaled.png r1 manage 13.9 K 2011-08-28 - 22:40 MatthiasSchroederHH  
PDFpdf c_puRA2_HTMHT_3J_dPhi_lepVeto_h_HT.pdf r1 manage 6.5 K 2011-08-28 - 22:40 MatthiasSchroederHH  
PNGpng c_puRA2_HTMHT_3J_dPhi_lepVeto_h_HT.png r1 manage 18.4 K 2011-08-28 - 22:40 MatthiasSchroederHH  
PDFpdf c_puRA2_HTMHT_3J_dPhi_lepVeto_h_MEff.pdf r1 manage 6.8 K 2011-08-28 - 22:40 MatthiasSchroederHH  
PNGpng c_puRA2_HTMHT_3J_dPhi_lepVeto_h_MEff.png r1 manage 19.7 K 2011-08-28 - 22:41 MatthiasSchroederHH  
PDFpdf c_puRA2_HTMHT_3J_dPhi_lepVeto_h_MHT.pdf r1 manage 7.4 K 2011-08-28 - 22:41 MatthiasSchroederHH  
PNGpng c_puRA2_HTMHT_3J_dPhi_lepVeto_h_MHT.png r1 manage 19.5 K 2011-08-28 - 22:41 MatthiasSchroederHH  
PDFpdf closurePlotsMix_baseline.pdf r1 manage 21.8 K 2011-08-28 - 22:42 MatthiasSchroederHH  
PNGpng closurePlotsMix_baseline.png r1 manage 159.7 K 2011-08-28 - 22:43 MatthiasSchroederHH  
PDFpdf combined_Exclusion_m0_m12_tb10.pdf r1 manage 28.3 K 2011-08-28 - 22:43 MatthiasSchroederHH  
PNGpng combined_Exclusion_m0_m12_tb10.png r1 manage 215.6 K 2011-08-28 - 22:43 MatthiasSchroederHH  
C source code filec combined_Exclusion_m0_m12_tb10_OnlyRA2LimitCurves.C r1 manage 30.4 K 2011-08-28 - 22:43 MatthiasSchroederHH  
C source code filec cvsE_sel0.C r1 manage 133.5 K 2011-11-08 - 05:58 GheorgheLungu msugra efficiencies baseline - script
PDFpdf cvsE_sel0.pdf r3 r2 r1 manage 23.7 K 2011-11-08 - 05:56 GheorgheLungu msugra efficiencies baseline
PNGpng cvsE_sel0.png r3 r2 r1 manage 18.3 K 2011-11-08 - 05:57 GheorgheLungu msugra efficiencies baseline -png
C source code filec cvsE_sel1.C r1 manage 125.5 K 2011-11-08 - 05:59 GheorgheLungu msugra efficiencies high MHT - script
PDFpdf cvsE_sel1.pdf r3 r2 r1 manage 22.6 K 2011-11-08 - 05:58 GheorgheLungu msugra efficiencies high MHT
PNGpng cvsE_sel1.png r3 r2 r1 manage 16.5 K 2011-11-08 - 05:59 GheorgheLungu msugra efficiencies high MHT - png
C source code filec cvsE_sel2.C r1 manage 131.6 K 2011-11-08 - 06:00 GheorgheLungu msugra efficiencies high HT - script
PDFpdf cvsE_sel2.pdf r3 r2 r1 manage 23.3 K 2011-11-08 - 06:00 GheorgheLungu msugra efficiencies high HT
PNGpng cvsE_sel2.png r3 r2 r1 manage 17.5 K 2011-11-08 - 06:00 GheorgheLungu msugra efficiencies high HT - png
PDFpdf h_limitRA2_T1_best.pdf r1 manage 9.4 K 2011-11-18 - 21:14 MariarosariaDalfonso  
PNGpng h_limitRA2_T1_best.png r1 manage 138.3 K 2011-11-18 - 21:12 MariarosariaDalfonso  
PDFpdf h_limitRA2_T2_best.pdf r1 manage 9.2 K 2011-11-18 - 21:14 MariarosariaDalfonso  
PNGpng h_limitRA2_T2_best.png r1 manage 130.2 K 2011-11-18 - 21:11 MariarosariaDalfonso  
PNGpng h_limitRA2_T5zz_best.png r1 manage 130.0 K 2011-11-18 - 21:24 MariarosariaDalfonso  
PDFpdf h_selRA2_T1_best.pdf r1 manage 7.7 K 2011-11-18 - 21:13 MariarosariaDalfonso  
PNGpng h_selRA2_T1_best.png r1 manage 102.4 K 2011-11-18 - 21:11 MariarosariaDalfonso  
PDFpdf h_selRA2_T2_best.pdf r1 manage 7.7 K 2011-11-18 - 21:13 MariarosariaDalfonso  
PNGpng h_selRA2_T2_best.png r1 manage 101.5 K 2011-11-18 - 21:10 MariarosariaDalfonso  
PDFpdf h_selRA2_T5zz_best.pdf r1 manage 7.1 K 2011-11-18 - 21:12 MariarosariaDalfonso  
PNGpng h_selRA2_T5zz_best.png r1 manage 103.4 K 2011-11-18 - 21:10 MariarosariaDalfonso  
Edit | Attach | Watch | Print version | History: r7 < r6 < r5 < r4 < r3 | Backlinks | Raw View | WYSIWYG | More topic actions
Topic revision: r7 - 2012-04-09 - MariarosariaDalfonso
 
    • Cern Search Icon Cern Search
    • TWiki Search Icon TWiki Search
    • Google Search Icon Google Search

    CMSPublic All webs login

This site is powered by the TWiki collaboration platform Powered by PerlCopyright &© 2008-2019 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding TWiki? Send feedback