Inclusive search for new physics at CMS with the jets and missing momentum signature

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 of 36/pb of proton-proton collisions at √s=7TeV acquired by the CMS detector at the LHC in 2010. There are three main background components. One is irreducible, from Z+jets events, with the Z decaying to neutrinos. A second comes from W+jets and top events where W decay yields a lepton that is not identified or a tau that decays hadronically. The third arises from QCD multi-jets where the missing momentum originates from jet mis-measurements, heavy-flavour decays, or instrumental effects. All these backgrounds are estimated from the data. No excess of events over backgrounds is observed. Exclusion limits are presented for the Constrained Minimal Supersymmetric extension of the Standard Model (CMSSM). Cross section limits are also presented using simplified models with generic particles decaying to one or two jets and an undetected particle.

Plots from SUS-10-005 PAPER ( click on plot to get .pdf )

Figure Abbreviated Caption
MHT.png MHT distribution data-MC comparison. The data MHT distribution is saved in the this file
HT.png HT distribution data-MC comparison.The data HT distribution is saved in this file
QCD170toInfpythia6_rs_vs_mc_spectra_baseline_mht.png The MHT distribution from the R&S method applied to simulation events, compared to the actual MC distribution (MC truth).
QCD170toInfpythia6_rs_vs_mc_spectra_baseline_ht.png The HT distribution from the R&S method applied to simulation events, compared to the actual MC distribution (MC truth).
pf_ptRes_wrt_badFrac_logy.png Resolution distribution of simulated jets for various values of expected momentum loss due to masked ECAL channels, as stated in the legend.
pf_ptRes_populations_logy.png Contributions to the total resolution distribution of simulated jets, categorised into populations as stated in the legend.
SigAccMHT_m0_m12_tb10.png Total signal efficiency for the MHT selection as a function of m0 and m1/2. Other param are tb10, mu>0, A0=0.
SigAccHT_m0_m12_tb10.png Total signal efficiency for the HT selection as a function of m0 and m1/2. Other param are tb10, mu>0, A0=0.
Exclusion_m0_m12_tb10_NoSigHypPseudoData_NoAtlas.png The expected and observed 95% CL upper limits in the CMSSM m0-m1/2 mass planes for LO and NLO cross sections. The \pm 1 standard deviation (sigma) band corresponds to the expected limit. The contours are the combination of the HT and MHT selections such that the contours are the enveloppe with respect to the best sensitivity. CMSSM param are tb10, mu>0, A0=0.
Exclusion_mGl_mSql_tb10_NoSigHypPseudoData.png The expected and observed 95% CL upper limits in the CMSSM gluino-squark mass planes for LO and NLO cross sections. The \pm 1 standard deviation (sigma) band corresponds to the expected limit. The contours are the combination of the HT and MHT selections such that the contours are the enveloppe with respect to the best sensitivity. CMSSM param are tb10, mu>0, A0=0.
acc_T1_MHT.png Total high-MHT selection efficiency for gluino production as a function of the gluino mass and the LSP mass.
acc_T2_MHT.png Total high-MHT selection efficiency for squark production as a function of the squark mass and the LSP mass.
limit_T1_MHT.png CL upper limits on the gluino pair-production cross sections for the high-MHT selection, as a function of the gluino mass and the LSP mass. The contours where the reference cross section and three times this cross section can be excluded are shown.
limit_T2_MHT.png CL upper limits on the squark pair-production cross sections for the high-MHT selection, as a function of the squark mass and the LSP mass. The contours where the reference cross section and three times this cross section can be excluded are shown.

Plots from SUS-10-005 PAS (not appearing in the paper) ( click on plot to get .pdf )

Figure Abbreviated Caption
MHTMHT_r.png Closure Test of LostLepton Method in MHT
HTHT_r.png Closure Test of LostLepton Method in HT
QCD170toInfpythia6_rs_vs_mc_spectra.png Spectra of R+S prediction compared to fully simulated MC distributions, for events passing cuts as indicated in the legend.
QCD170toInfpythia6_R_plus_S_performance.png Ratio of R+S predicted over fully simulated MC distributions, for events passing cuts as indicated in the legend. The grey shaded area indicate where all denominators vanish.

TailSig25-Inf_PF_EtaBin0_PtBin2_Pt3Bin0_PtSmearAsymTail.png Di-jet asymmetry for adjusted Monte Carlo and data. The area starting from the red line defines the window which is kept fixed during the extrapolation down to prelT,3 = 0. For comparison, the green shaded area show the fraction of events in the asymmetry window under the hypothesis of a purely Gaussian shape
TailSig25-Inf_PF_EtaBin0_PtBin2_Extrapolation.png Extrapolation of non fraction of events with high diJet asymmetry down to prelT,3 = 0. For comparison, green markers show the fraction of events in the asymmetry window under the hypothesis of a purely Gaussian shape
TailScalingFactorsSig25-Inf_PF_Eta0.png Not in PAS: Tail scaling factors as function of pT for ΙetaΙ<1.1
TailScalingFactorsSig25-Inf_PF_Eta1.png Not in PAS: Tail scaling factors as function of pT for 1.1<ΙetaΙ<1.7
MHTSlicesGaussFits.png Distribution of DeltaPhiMin in slices of HT for simulated QCD events. Gaussian fits with a fixed mean=0 are applied
DataQCD_SlicesPlot.png Sigma of the Gaussian fits of MHT slices from simulation and compared to data. The deviation at high MHT from the exponential dependence for the data is due to contamination from SM background with real MHT.
Closure_ExpoGauss_MadGraph.png Closure test of the factorization method for the baseline selection of the ratio r for a MADGRAPH QCD sample
Closure_ExpoGauss_All.png Factorization method: Background prediction for different simulations. Bins 12 show PYTHIA and MADGRAPH QCD simulation, bins 37 show pseudo-simulated QCD samples (45: scaling the jet response tail, 6: additional jet resolution smearing of 20%, 7: increased low jet energy response tail).

ra2_results_table.png Predicted event yields from the different background estimation methods for the baseline selection and for the high-MHT and high-HT search selections. In the limit calculations the background estimates used are the R+S method for QCD, Z→νν from photons, and the W/ttbar lost-lepton and hadronic tau predictions.
<!
SigAccHT_m0_m12_tb10.png Signal Acceptance for the HT selection in the m0 - m1/2 plane for CMSSM for tan(beta)=10.
SigAccMHT_m0_m12_tb10.png Signal Acceptance for the MHT selection in the m0 - m1/2 plane for CMSSM for tan(beta)=10.
CMSSM_m0_m12_tb10.png Exclusion contour in the m0 - m1/2 plane for CMSSM for tan(beta)=10. The shown exclusion contour is the best envelope of the obtained contours using the MHT and HT search selection. For low m0 ~< 500 GeV the MHT selection is more sensitive than the HT selection. The background estimation is obtained by data-driven methods and therefore subject to possible signal-contamination. The possible signal contamination at a given point in the parameter space, which varies with the CMSSM cross-section and acceptance, is subtracted from the background event yield. The lines of the observed and expected limits can cross each other, because (i) of the two different selections combined in this plot, and because (ii) the signal contamination and therefore the corrected backgound estimation varies slightly with m0 and m1/2.
CMSSM_m0_m12_tb10_Bayes.png Exclusion contour in the m0 - m1/2 plane for CMSSM for tan(beta)=10. Two independent statistical methods (CLs and Bayes) were used to calculated the two NLO limits compared in this plot. See above for a description of the limit contours.
CMSSM_mGl_mSql_tb10.png Exclusion contour in the gluino mass - squark mass plane for CMSSM for tan(beta)=10. See above for a description of the limit contours.
CMSSM_m0_m12_tb3.png Exclusion contour in the m0 - m1/2 plane for CMSSM for tan(beta)=3. See above for a description of the limit contours.
CMSSM_m0_m12_tb50.png Exclusion contour in the m0 - m1/2 plane for CMSSM for tan(beta)=50. See above for a description of the limit contours.
CMSSM_m0_m12_Comp.png Exclusion contour in the m0 - m1/2 plane for CMSSM for the three different values of tan(beta)=3, 10, 50. The NLO expected and observed limits are shown. This plot shows, that there is basically no dependence of the limits on the value of tan(beta). See above for a description of the limit contours.
!> The following result are saved in the electronic format in RA2_SMS_results.root.(N.B. use the colz option to draw the histograms)
topology Acceptance Relative Experimental Uncertainty Relative Theoretical uncertainty 95% exclusion limit cross section x BR Abbreviated Caption
    jet energy scale and resolution, MCstatistics initial and final state radiation, PDF this take into account the Experimental and Theoretical Uncertainties and an additional absolute uncertainty of 2% to taken into account for trigger and cleaning efficiency and 4% for the luminosity; the reference cross section is drawn in center of the bin excluded  
t1.png acc_T1_MHT.png exp_T1_MHT.png teo_T1_MHT.png limit_T1_MHT.png Signal acceptance, experimental and theoretical uncertainties, and exclusion limit cross section for high MHT search region and gluino pair production.
t1.png acc_T1_HT.png exp_T1_HT.png teo_T1_HT.png limit_T1_HT.png Signal acceptance, experimental and theoretical uncertainties, and exclusion limit cross section for high HT search region and gluino pair production.
t2.png acc_T2_MHT.png exp_T2_MHT.png teo_T2_MHT.png limit_T2_MHT.png Signal acceptance, experimental and theoretical uncertainties, and exclusion limit cross section for high MHT search region and squark pair production.
t2.png acc_T2_HT.png exp_T2_HT.png teo_T2_HT.png limit_T2_HT.png Signal acceptance, experimental and theoretical uncertainties, and exclusion limit cross section for high HT search region and squark pair production.

148953-49-70626194-700GeVrhophi.png Event 70626194, in luminosity section 49 of run 148953. r-φ view of the highest-/HT event passing the search selections.
Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf 148953-49-70626194-700GeVrhophi.pdf r1 manage 107.1 K 2011-03-16 - 20:53 SueAnnKoay  
PNGpng 148953-49-70626194-700GeVrhophi.png r1 manage 137.6 K 2011-03-16 - 20:53 SueAnnKoay  
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PNGpng CMSSM_m0_m12_Comp.png r1 manage 85.6 K 2011-03-14 - 12:08 ChristianAutermann  
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PNGpng CMSSM_m0_m12_tb10.png r2 r1 manage 163.9 K 2011-04-02 - 12:08 ChristianAutermann  
PDFpdf CMSSM_m0_m12_tb10_Bayes.pdf r2 r1 manage 27.1 K 2011-04-02 - 12:09 ChristianAutermann  
PNGpng CMSSM_m0_m12_tb10_Bayes.png r2 r1 manage 193.7 K 2011-04-02 - 12:09 ChristianAutermann  
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PDFpdf CMSSM_m0_m12_tb50.pdf r1 manage 23.4 K 2011-04-02 - 12:14 ChristianAutermann  
PNGpng CMSSM_m0_m12_tb50.png r1 manage 117.6 K 2011-04-02 - 12:13 ChristianAutermann  
PDFpdf CMSSM_mGl_mSql_tb10.pdf r1 manage 17.7 K 2011-04-02 - 12:15 ChristianAutermann  
PNGpng CMSSM_mGl_mSql_tb10.png r1 manage 95.1 K 2011-04-02 - 12:14 ChristianAutermann  
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PNGpng Closure_ExpoGauss_All.png r1 manage 62.7 K 2011-03-15 - 17:35 ChristianSander  
PDFpdf Closure_ExpoGauss_MadGraph.pdf r1 manage 25.5 K 2011-03-15 - 17:35 ChristianSander  
PNGpng Closure_ExpoGauss_MadGraph.png r1 manage 68.4 K 2011-03-15 - 17:35 ChristianSander  
PDFpdf DataQCD_SlicesPlot.pdf r1 manage 15.8 K 2011-03-15 - 17:35 ChristianSander  
PNGpng DataQCD_SlicesPlot.png r1 manage 58.3 K 2011-03-15 - 17:36 ChristianSander  
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PDFpdf HTHT_r.pdf r2 r1 manage 6.3 K 2011-03-16 - 16:19 UnknownUser  
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PDFpdf MHTMHT_r.pdf r2 r1 manage 5.8 K 2011-03-16 - 16:22 UnknownUser  
PNGpng MHTMHT_r.png r5 r4 r3 r2 r1 manage 65.0 K 2011-03-16 - 17:35 UnknownUser  
PDFpdf MHTSlicesGaussFits.pdf r1 manage 22.7 K 2011-03-15 - 17:36 ChristianSander  
PNGpng MHTSlicesGaussFits.png r1 manage 98.1 K 2011-03-15 - 17:36 ChristianSander  
PDFpdf QCD170toInfpythia6_R_plus_S_performance.pdf r1 manage 20.0 K 2011-03-16 - 19:36 SueAnnKoay  
PNGpng QCD170toInfpythia6_R_plus_S_performance.png r1 manage 30.4 K 2011-03-16 - 19:36 SueAnnKoay  
PDFpdf QCD170toInfpythia6_rs_vs_mc_spectra.pdf r2 r1 manage 24.7 K 2011-03-24 - 18:17 SueAnnKoay  
PNGpng QCD170toInfpythia6_rs_vs_mc_spectra.png r2 r1 manage 41.0 K 2011-03-24 - 18:18 SueAnnKoay  
Unknown file formatroot RA2_SMS_results.root r1 manage 62.2 K 2011-04-08 - 16:11 MariarosariaDalfonso  
Unknown file formatroot SUS10005_ht_mht_data_distribution.root r1 manage 4.6 K 2011-06-15 - 22:31 MariarosariaDalfonso  
PDFpdf T1.pdf r1 manage 33.7 K 2011-04-08 - 16:23 MariarosariaDalfonso  
PDFpdf T2.pdf r1 manage 26.9 K 2011-04-08 - 16:23 MariarosariaDalfonso  
PDFpdf TailScalingFactorsSig25-Inf_PF_Eta0.pdf r1 manage 9.4 K 2011-03-15 - 18:33 ChristianSander  
PNGpng TailScalingFactorsSig25-Inf_PF_Eta0.png r1 manage 60.8 K 2011-03-15 - 18:33 ChristianSander  
PDFpdf TailScalingFactorsSig25-Inf_PF_Eta1.pdf r1 manage 9.3 K 2011-03-15 - 18:33 ChristianSander  
PNGpng TailScalingFactorsSig25-Inf_PF_Eta1.png r1 manage 60.1 K 2011-03-15 - 18:33 ChristianSander  
PDFpdf TailSig25-Inf_PF_EtaBin0_PtBin2_Extrapolation.pdf r1 manage 11.4 K 2011-03-15 - 18:33 ChristianSander  
PNGpng TailSig25-Inf_PF_EtaBin0_PtBin2_Extrapolation.png r1 manage 93.3 K 2011-03-15 - 18:34 ChristianSander  
PDFpdf TailSig25-Inf_PF_EtaBin0_PtBin2_Pt3Bin0_PtSmearAsymTail.pdf r1 manage 15.4 K 2011-03-15 - 18:34 ChristianSander  
PNGpng TailSig25-Inf_PF_EtaBin0_PtBin2_Pt3Bin0_PtSmearAsymTail.png r1 manage 93.7 K 2011-03-15 - 18:34 ChristianSander  
PDFpdf acc_T1_HT.pdf r2 r1 manage 15.9 K 2011-03-16 - 23:21 SueAnnKoay  
PDFpdf acc_T2_HT.pdf r2 r1 manage 15.8 K 2011-03-16 - 23:26 SueAnnKoay  
PDFpdf exp_T1_MHT.pdf r2 r1 manage 15.9 K 2011-03-16 - 23:31 SueAnnKoay  
PDFpdf exp_T2_HT.pdf r2 r1 manage 15.9 K 2011-03-16 - 23:32 SueAnnKoay  
PDFpdf exp_T2_MHT.pdf r2 r1 manage 15.9 K 2011-03-16 - 23:32 SueAnnKoay  
PDFpdf lostlepton.pdf r1 manage 51.5 K 2011-03-15 - 12:09 ChristianAutermann  
PNGpng lostlepton.png r1 manage 65.6 K 2011-03-15 - 12:08 ChristianAutermann  
PDFpdf lowest_unprescaled_HT_trigger_eff_2010data.pdf r3 r2 r1 manage 15.9 K 2011-03-17 - 00:07 SueAnnKoay  
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PDFpdf pf_ptRes_wrt_badFrac_logy.pdf r2 r1 manage 220.8 K 2011-06-07 - 17:58 SueAnnKoay  
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PDFpdf ra2_results_table.pdf r2 r1 manage 28.4 K 2011-03-25 - 16:52 StevenLowette  
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PNGpng t1.png r2 r1 manage 60.0 K 2011-04-08 - 16:34 MariarosariaDalfonso  
PNGpng t2.png r2 r1 manage 56.2 K 2011-04-08 - 16:35 MariarosariaDalfonso  
PDFpdf teo_T1_MHT.pdf r2 r1 manage 15.7 K 2011-03-16 - 23:33 SueAnnKoay  
PDFpdf teo_T2_HT.pdf r2 r1 manage 15.7 K 2011-03-16 - 23:34 SueAnnKoay  
PDFpdf teo_T2_MHT.pdf r2 r1 manage 15.7 K 2011-03-16 - 23:35 SueAnnKoay  
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