Search for supersymmetry in events with a lepton and missing energy at the LHC

Abstract

Preliminary results are reported from a search for physics beyond the standard model (SM) in proton-proton collisions at a center-of-mass energy of 7 TeV, focusing on the signature with a single, isolated, high-transverse momentum lepton (electron or muon), energetic jets, and large missing transverse momentum. The data sample comprises an integrated luminosity of 4.7 fb⁻¹, recorded by the CMS experiment at the LHC. The search is motivated by models of new physics, including supersymmetry. SM backgrounds are determined from control samples in the data using two complementary methods. The observed yields of events in the signal region are consistent with the background predictions. The results are interpreted in terms of limits on the parameter space for the constrained minimal supersymmetric extension of the standard model.

Link to approved PAS pending.

Approved Plots from SUS-12-010 from Lepton Spectrum Method ( click on [PDF] to get .pdf )

Observed ETmiss distributions in data compared with predicted distributions (red bars) in the combined electron and muon channels, for HT > 500 GeV. The red-bar histogram includes the total single lepton, dilepton, and single τ background prediction, where the error band shows the uncertainty from the ETmiss scale. The blue histogram shows the contribution from just the dilepton and single τ backgrounds. The distributions for SUSY benchmark models LM3 and LM6 are overlaid for comparison. (A version on a linear scale is available here

• MET Prediction with HT>500 GeV log scale:(PDF):
  

• MET Prediction with HT>500 GeV real scale:(PDF):
  

• MET Prediction with HT>750 GeV log scale:( PDF):
  

• MET Prediction with HT>750 GeV real scale:(PDF):
  

• MET Prediction with HT>1000 GeV log scale:(PDF):
  

• MET Prediction with HT>1000 GeV real scale:(PDF):
  

• Dileptons Data Prediction HT>750 4.7 fb⁻¹:(PDF):
  | The simulation has been scaled to the integral of the prediction in data. |

• Dileptons MC Closure HT>750 4.7 fb⁻¹:(PDF):
  

• SingleTau Data Prediction HT>750 4.7 fb⁻¹:(PDF):
  | The simulation has been scaled to the integral of the prediction in data. |

• SingleTau MC Closure HT>750 4.7 fb⁻¹:(PDF):
  

• Prediction Tablet for Lepton Spectrum Method with HT>500, Total (mu,e):(PDF):
  

• Prediction Tablet for Lepton Spectrum Method with HT>750, Total (mu,e):(PDF):
  

• Prediction Tablet for Lepton Spectrum Method with HT>1000, Total (mu,e):(PDF):
  

• Lepton Spectrum Systematic Uncertainties:(PDF):
  

• LS limit plot for HT>500 GeV (PDF):
  

• LS limit plot for HT>750 GeV (PDF):
  

• LS limit plot for HT>1000 GeV (PDF):
  

Approved Plots from SUS-12-010 from Lepton Projection Method ( click on [PDF] to get .pdf )

• Event yields in data and MC normalized to 4.7 fb⁻¹ for the muon search sample with ≥ 3 jets and HT > 500 GeV. The MC yields (in columns "Total MC") are listed for reference only. The column labeled "SM estimate" lists the number of events expected from SM processes, as determined by the data-driven method. The uncertainties listed for the MC are only statistical. The uncertainties listed for the SM estimate are first the statistical uncertainty from the control region and second all other systematic uncertainties. (PDF):
  

• Event yields in data and MC normalized to 4.7 fb⁻¹ for the muon search sample with ≥ 3 jets and HT > 750 GeV. The MC yields (in columns "Total MC") are listed for reference only. The column labeled "SM estimate" lists the number of events expected from SM processes, as determined by the data-driven method. The uncertainties listed for the MC are only statistical. The uncertainties listed for the SM estimate are first the statistical uncertainty from the control region and second all other systematic uncertainties. (PDF):
  

• Event yields in data and MC normalized to 4.7 fb⁻¹ for the muon search sample with ≥ 3 jets in different HT bins. The MC yields (in columns "Total MC") are listed for reference only. The column labeled "SM estimate" lists the number of events expected from SM processes, as determined by the data-driven method. The uncertainties listed for the MC are only statistical. The uncertainties listed for the SM estimate are first the statistical uncertainty from the control region and second all other systematic uncertainties. (PDF):
  

• Event yields in data and predictions of the numbers of EWK and QCD events for the electron search sample with ≥ 3 jets and HT > 500 GeV. The column labeled "SM estimate" lists the number of events expected from SM processes, as determined by the data-driven method. The uncertainties listed for the MC contributions are only statistical. The uncertainties listed for the SM estimate are first the statistical uncertainty from the fit to the control region and second all other systematic uncertainties. (PDF):
  

• Event yields in data and predictions of the numbers of EWK and QCD events for the electron search sample with ≥ 3 jets and HT > 750 GeV. The column labeled "SM estimate" lists the number of events expected from SM processes, as determined by the data-driven method. The uncertainties listed for the MC contributions are only statistical. The uncertainties listed for the SM estimate are first the statistical uncertainty from the fit to the control region and second all other systematic uncertainties. (PDF):
  

• Event yields in data and predictions of the numbers of EWK and QCD events for the electron search sample with ≥ 3 jets in different HT bins. The column labeled "SM estimate" lists the number of events expected from SM processes, as determined by the data-driven method. The uncertainties listed for the MC contributions are only statistical. The uncertainties listed for the SM estimate are first the statistical uncertainty from the fit to the control region and second all other systematic uncertainties. (PDF):
  

• Sources of systematic uncertainty and their effect on on the predicted background in the muon search sample with ≥ 3 jets and HT > 500 GeV (PDF):
  

• Sources of systematic uncertainty and their effect on on the predicted background in the muon search sample with ≥ 3 jets and HT > 750 GeV (PDF):
  

• Sources of systematic uncertainty and their effect on on the predicted background in the muon search sample with ≥ 3 jets and HT > 1000 GeV (PDF):
  

• Sources of systematic uncertainty and their effect on on the predicted background in the electron search sample with ≥ 3 jets and HT > 500 GeV (PDF):
  

• Sources of systematic uncertainty and their effect on on the predicted background in the electron search sample with ≥ 3 jets and HT > 750 GeV (PDF):
  

• Sources of systematic uncertainty and their effect on on the predicted background in the electron search sample with ≥ 3 jets and HT > 1000 GeV (PDF):
  

• LP distributions for SUSY [LM3 and LM6] and SM processes for HT>500 GeV and STlep>450 GeV , scaled at 4.7 fb⁻¹ (PDF):
  

• LP distributions for SUSY [LM3 and LM6] and total SM for HT>500 GeV and STlep>450 GeV , normalized to 1. (PDF):
  

• Data and fit results for the predictions for the LP distribution in the muon search sample for events with HT>500 GeV and 250<STlep<350 GeV. (PDF):
  

• Data and fit results for the predictions for the LP distribution in the muon search sample for events with HT>500 GeV and 350<STlep<450 GeV. (PDF):
  

• Data and fit results for the predictions for the LP distribution in the muon search sample for events with HT>500 GeV and STlep>450 GeV. (PDF):
  

• Data and fit results for the predictions for the LP distribution in the muon search sample for events with HT>1000 GeV and 250<STlep<350 GeV. (PDF):
  

• Data and fit results for the predictions for the LP distribution in the muon search sample for events with HT>1000 GeV and 350<STlep<450 GeV. (PDF):
  

• Data and fit results for the predictions for the LP distribution in the muon search sample for events with HT>1000 GeV and STlep>450 GeV. (PDF):
  

• Fit results on data in the electron search sample for events with HT>500 and 150<STlep<250. The fit is performed in the control region (Lp>0.3) and the result is extrapolated into the signal region (Lp<0.15) (PDF):
  

• Fit results on data in the electron search sample for events with HT>500 and 250<STlep<350. The fit is performed in the control region (LP>0.3) and the result is extrapolated into the signal region (Lp<0.15) (PDF):
  

• Data and fit results for the predictions for the LP distribution in the electron search sample for events with HT>500 GeV and 250<STlep<350 GeV. (PDF):
  

• Data and fit results for the predictions for the LP distribution in the electron search sample for events with HT>500 GeV and 350<STlep<450 GeV. (PDF):
  

• Data and fit results for the predictions for the LP distribution in the electron search sample for events with HT>500 GeV and STlep>450 GeV. (PDF):
  

• Data and fit results for the predictions for the LP distribution in the electron search sample for events with HT>750 GeV and 250<STlep<350 GeV. (PDF):
  

• Data and fit results for the predictions for the LP distribution in the electron search sample for events with HT>750 GeV and 350<STlep<450 GeV. (PDF):
  

• Data and fit results for the predictions for the LP distribution in the electron search sample for events with HT>750 GeV and STlep>450 GeV. (PDF):
  

• Data and fit results for the predictions for the LP distribution in the electron search sample for events with HT>1000 GeV and 250<STlep<350 GeV. (PDF):
  

• Data and fit results for the predictions for the LP distribution in the electron search sample for events with HT>1000 GeV and 350<STlep<450 GeV. (PDF):
  

• Data and fit results for the predictions for the LP distribution in the electron search sample for events with HT>1000 GeV and STlep>450 GeV. (PDF):
  

• Comparison of the number of events observed in the data and the expectations from all SM processes as determined by the data-driven methods, in the muon search sample with HT > 500 GeV in all STlep bins. (PDF):
  

• Comparison of the number of events observed in the data and the expectations from all SM processes as determined by the data-driven methods, in the muon search sample with HT > 750 GeV in all STlep bins. (PDF):
  

• Comparison of the number of events observed in the data and the expectations from all SM processes as determined by the data-driven methods, in the muon search sample with HT > 1000 GeV in all STlep bins. (PDF):
  

• Comparison of the number of events observed in the data and the expectations from all SM processes as determined by the data-driven methods, in the muon search sample in all HT and STlep bins. (PDF):
  

• Comparison of the number of events observed in the data and the expectations from all SM processes as determined by the data-driven methods, in the electron search sample with HT > 500 GeV in all STlep bins. (PDF):
  

• Comparison of the number of events observed in the data and the expectations from all SM processes as determined by the data-driven methods, in the electron search sample with HT > 750 GeV in all STlep bins. (PDF):
  

• Comparison of the number of events observed in the data and the expectations from all SM processes as determined by the data-driven methods, in the electron search sample with HT > 1000 GeV in all STlep bins. (PDF):
  

• Comparison of the number of events observed in the data and the expectations from all SM processes as determined by the data-driven methods, in the electron search sample in all HT and STlep bins. (PDF):
  

• LP limit plot for HT>500 GeV (PDF):
  

• LP limit plot for HT>750 GeV (PDF):
  

• LP limit plot for HT>1000 GeV (PDF):
  

Approved Plots from SUS-12-010 from combined results ( click on [PDF] to get .pdf )

• The 95% CL exclusion contours for the LP and LS methods obtained from the HT>500 GeV search region are shown in the cMSSM m_1/2 vs m₀ plane. The LS observed limit is shown by the solid blue line; the LS expected limit is shown by the dashed blue line. The cyan hatched band indicates the LS ±1σ range of expected limits. The LP observed limit is shown by the solid red line; the LP expected limit is shown by the dashed red line. The magenta hatched band indicates the LP ±1σ range of expected limits. The expected limit bands do not include the theoretical uncertainties in the cross-section due to uncertainties in PDFs, renormalization and factorization scales. (PDF):
  

• The 95% CL exclusion contours for the LP and LS methods obtained from the HT>750 GeV search region are shown in the cMSSM m_1/2 vs m₀ plane. The LS observed limit is shown by the solid blue line; the LS expected limit is shown by the dashed blue line. The cyan hatched band indicates the LS ±1σ range of expected limits. The LP observed limit is shown by the solid red line; the LP expected limit is shown by the dashed red line. The magenta hatched band indicates the LP ±1σ range of expected limits. The expected limit bands do not include the theoretical uncertainties in the cross-section due to uncertainties in PDFs, renormalization and factorization scales. (PDF):
  

• The 95% CL exclusion contours for the LP and LS methods obtained from the HT>500 GeV search region are shown in the cMSSM m_1/2 vs m₀ plane. The LS observed limit is shown by the solid blue line; the LS expected limit is shown by the dashed blue line. The cyan hatched band indicates the LS ±1σ range of expected limits. The LP observed limit is shown by the solid red line; the LP expected limit is shown by the dashed red line. The magenta hatched band indicates the LP ±1σ range of expected limits. The expected limit bands do not include the theoretical uncertainties in the cross-section due to uncertainties in PDFs, renormalization and factorization scales. (PDF):
  

-- WingTo - 27-Feb-2012