SUSY Experimental Results from CMS and ATLAS

Transcription

1 SUSY Experimental Results from CMS and ATLAS Kenichi Hatakeyama Baylor University Review of Discovery Physics Results from ICHEP Argonne National Laboratory July 17, 2012

2 Why SUSY Now? Three very compelling reasons: Allows unification of gauge couplings Can predict a dark matter particle candidate Provide a solution to the hierarchy problem: Light Higgs (125 GeV!?) needs new physics to stabilize mass July 17, 2012 SUSY Experimental Results 2

3 Why SUSY Now? Three very compelling reasons: Allows unification of gauge couplings Can predict a dark matter particle candidate Provide a solution to the hierarchy problem: Light Higgs (125 GeV!?) needs new physics to stabilize mass The contribution from a Dirac fermion loop diverges quadratically July 17, 2012 SUSY Experimental Results 3

4 Why SUSY Now? Three very compelling reasons: Allows unification of gauge couplings Can predict a dark matter particle candidate Provide a solution to the hierarchy problem: Light Higgs (125 GeV!?) needs new physics to stabilize mass The contribution from a Dirac fermion loop diverges quadratically The contribution from opposite spin super-partners would cancel the divergence resolving the hierarchy problem July 17, 2012 SUSY Experimental Results 4

5 SUSY Results from CMS+ATLAS Many new results for ICHEP from CMS and ATLAS >=10 public notes or papers from both CMS and ATLAS ~15 talks on LHC SUSY-related searches in the parallel sessions Not really possible to cover all these wonderful new results. For more details, visit CMS & ATLAS pages: or ICHEP SUSY session indico: In this talk, I will cover highlights from many results shown at ICHEP 2012, and let s discuss where we are and where we are heading to. July 17, 2012 SUSY Experimental Results 5

6 SUSY Searches at the LHC Many powerful inclusive searches have been pursued Searching in a broad spectrum of new physics scenarios main sensitivities to gluino/squark production Different observables & search strategies have been used for complementarities and robustness Some of them are even reaching to 3 rd generation sparticles Cross Section (pb) More targeted searches also started to be very vigorously pursued 3 rd generation sparticles, gaugino production, etc Difficult phase space (compressed spectra) and more SUSY scenarios July 17, 2012 SUSY Experimental Results 6

7 Missing ET Missing ET (MET) is the key variable for a majority of SUSY searches MET performance in ATLAS and CMS is comparable ATLAS (hadron) calorimeter performs better. CMS compensates using particle-flow technique Eur. Phys. J. C72 (2012) 1844 J. Instrum.6 (2011) P09001 July 17, 2012 SUSY Experimental Results 7

8 MET with Pileups Missing ET can be sensitive to pileup (additional pp) interactions Average pileup ~10 in Doubled in Both CMS and ATLAS have good modeling of pileup in simulation and also reducing pileup effects 2011 data Number of reconstructed primary vertices ATLAS Calor 2012 CMS DPS July 17, 2012 SUSY Experimental Results 8

9 Inclusive Searches Both CMS & ATLAS have performed inclusive searches in various channels Inclusive searches cut on hadronic activities (HT, jet multiplicity) and METlike variables (MET, Meff, MHT, MET/ HT, MT2, αt, razor, etc) Searches with different lepton categories Different BG compositions & less BG with more leptons Different sensitivities to a variety of SUSY scenarios Adding b-jets lower backgrounds, become more sensitive SUSY 3 rd gen squark production Adding photons, taus allow to explore even more SUSY scenarios All hadronic Single lepton OS dileptons SS dileptons Multileptons QCD Z νν W+jets ttbar W+jets ttbar Z+jets ttbar ZZ/ZW/WW ttz/w Rare SM ttbar ZZ/ZW/WW ttz/w Rare SM More signal rate/more BG Smaller rate/more BG control July 17, 2012 SUSY Experimental Results 9

10 CMS-SUS , arxiv: Hadronic Search in Jets + MET Selection Search variables: Other variable (CMS-SUS ): 3 jets with η <2.5, pt>50 GeV Veto isolated e/mu Suppress W & Top BGs Δφ(MHT,j1,2,3) > 0.5,0.5,0.3 (rad) Suppress QCD background Backgrounds QCD Top & W+jets Z( νν)+jets Determined by data-driven techniques HT: Characterize visible energy of the event MHT: Object-based MET. Characterize energy carried by undetected particle. Classic, yet powerful. MT2: generalized MT for decay chains with two unobserved particles. MT2 peaks toward 0 and MT2<MET for QCD-like events. g ~ g ~ q ~ q ~ j j 0 χ 1 j j 0 χ 1 May 9,

11 Hadronic Search in Jets + MET Background estimation (data-driven): Z( νν)+jets γ+jets: remove γ, correct for Z( νν)/γ Z( ll)+jets: remove ll, correct for Br(Z νν/z ll) Top & W(lν)+jets: lost leptons (escape e/μ vetos) or W τ hadronic decays Start with μ+jets sample Lost leptons: Correct for lepton finding/losing probability Use e-μ universality W τ hadronic decays: Replace μ with hadronic τ response function QCD: Smear the well-balance events in QCD control sample May 9, 2011 MC-based backgrounds for illustration LM5*: m 0 =230GeV, m 1/2 =360 GeV, A 0 =0, tanβ=10, sign(μ)>0 CMS-SUS , arxiv:

12 CMSSM / msugra Inclusive SUSY results have been conventionally shown in the context of constrained MSSM / msugra CMSSM has only 5 parameters: universal scalar and gaugino masses, m 0, m 1/2, A 0, tanβ, sin(μ). Very predictive; however, the universality constraints result in significant restrictions on possible SUSY particle mass spectra Now, it s common to interprete results in more general topology-based simplified model m 1/2, common gaugino mass [GeV] m 0, common scalar mass [GeV] m(gluino) > 720 GeV m(squark) > 1.2 TeV July 17, 2012 SUSY Experimental Results 12

13 Simplified Model (SMS) Focus on topology instead of underlying physics model Any model with same topology (parent particle mass, decay chain, daughters mass) can be easily compared with experimental results. Building blocks that can be used to generalize to a more complete model -space j The gluino mass exclusions depends strongly on the LSP mass. The phase space in which the LSP and gluino (mother) masses are close to each other (compress spectra = small ΔM) are much less constrained g ~ g ~ j LSP LSP j j arxiv: arxiv: May 9,

14 All Hadronic Search with 6-9 Jets Motivation Analysis targeting models with longer decay chains: Many jets ( 6-9), Softer MET arxiv: Selection Events selected with multi-jet triggers Events with electron / muons vetoed Final selection variable is MET/ HT Backgrounds QCD multijet (inlcuding ttbar all hadronic), Leptonic (W+jets, Z+jets, and semi-, fully-leptonic ttbar) July 17, 2012 SUSY Experimental Results 14

15 All Hadronic Search with 6-9 Jets Background estimation QCD MET/ HT ~ MET significance: independent of jet multiplicity MET/ HT templates from low jet multiplicities Low MET/ HT used for normalization Leptonic background Control regions are formed by requiring leptons Use transfer functions (from MC) between control and signal regins g ~ t t LSP g ~ LSP t t July 17, 2012 SUSY Experimental Results 15

16 1-lepton Search with 2-4 Jets Selection ATLAS-CONF MT: Transverse mass from lepton & MET Meff : Sum over MET, pt of jets M inc eff : Sum over MET, pt of the lepton and all jets in the event. 2 hard - lepton Signal Regions (SRs): Optimized for CMSSM/MSUGRA and models with large mass spectra. Higher p T thresholds for all objects, higher jet multiplicities, tight cuts on MET Final discriminating variable M eff inc. 1 soft - lepton SR (new!): Optimized for models with compressed mass spectra. Low-p T thresholds for electrons (muons) and 2nd jet, high-p T leading jet (initial state radiation), tight cuts on MET. Final discriminating variable MET / Meff. July 17, 2012 SUSY Experimental Results 16

17 1-lepton Search with 2-4 Jets No significant excess Interpretation in CMSSM and SMS with m(squark) = m (gluino) 1200 GeV hard - lepton soft - lepton July 17, 2012 SUSY Experimental Results 17

18 CMS-SUS SS Dileptons with >=2 b Jets Same-sign lepton pairs are classic SUSY searches Leptons from many SUSY decay chains: chargino, neutralino, W, Z, sleptons Low SM backgrounds Adding b jets helps even more Lower backgrounds t bw can give even more leptons Selection 2 b-tagged jets with pt > 40 GeV Isolated same sign e or μ pair pt > 20 GeV M(ll) > 8 GeV to reject b s Reject extra leptons consistent with Z s MET > 30 GeV Low cut possible with dilepton triggers Gluino pair production with decays to real and virtual stops Sbottom pair production or gluino decays via sbottoms Up to 4 leptons + 2 b jets July 17, 2012 SUSY Experimental Results 18

19 SS Dileptons with >=2 b Jets Dominant Background ttbar (l+jets) with fake leptons: fake ratio with isolation extrapolation Charge mis-reconstruction: use Z s for x-check. Apply to ttbar dileptons Rare SM processes with high pt leptons & b-jets: estimate from MC July 17, 2012 SUSY Experimental Results 19

20 SS Dileptons with >=2 b Jets gluino virtual top squarks gluino on-shell top squarks Sbottom pair production July 17, 2012 SUSY Experimental Results 20

21 SS Dileptons with >=2 b Jets gluino virtual top squarks gluino on-shell top squarks Sbottom pair production July 17, 2012 SUSY Experimental Results 21

22 SS Dileptons with >=2 b Jets gluino virtual top squarks gluino on-shell top squarks Sbottom pair production Gluinos have been excluded with masses up to ~880 GeV Lower limit on the bottom squark mass of 408 GeV July 17, 2012 SUSY Experimental Results 22

23 CMS-SUS , CMS-SUS α T Search with 0,1,2,>=3 b s α T variable: QCD: Peak around 0.5 and tail to lower α T αt>0.55 Strong suppression of QCD BG Event Selection 2 jets with pt>50 GeV, η <3 Jet1 with η <2.5 & pt>100 GeV Veto isolated electrons, muons, and photons 8 HT bins starting from 275 GeV Binned in 0, 1, 2, and >=3 b-tag bins July 17, 2012 SUSY Experimental Results 23

24 α T Search with 0,1,2,>=3 b s Background estimation A binned likelihood fit using all control samples to maximize the total likelihood for top/w for QCD for Z(νν)+jets 0 b-jet Data Predicted background 2 b-jets July 17, 2012 SUSY Experimental Results 24

25 α T Search with 0,1,2,>=3 b s Strong constraints on various SUSY topologies q ~ LSP 7 TeV 7 TeV b ~ LSP q ~ LSP b ~ LSP g ~ g ~ t t LSP LSP t t 7 TeV 7 TeV July 17, 2012 SUSY Experimental Results 25 g ~ g ~ b b LSP LSP b b

26 α T Search with 0,1,2,>=3 b s Strong constraints on various SUSY topologies q ~ LSP 7 TeV 7 TeV b ~ LSP q ~ LSP b ~ LSP g ~ g ~ t t LSP LSP t t 7 TeV 7 TeV 8 TeV! July 17, 2012 SUSY Experimental Results 26 g ~ g ~ t t LSP LSP t t

27 Direct Stops in Inclusive Searches ~ t LSP α T : CMS-SUS ~ t LSP Razor: CMS-SUS Search with Razor variables: M R & R Designed to characterize pair-production of heavy particles. Combine all particles into two hemispheres, boost back to rest frame (see Will Reece s talk at ICHEP for more details) Even inclusive searches started to become sensitive to direct stop production! July 17, 2012 SUSY Experimental Results 27

28 ATLAS-CONF Gluino Mediated Stop/Sbottom Search Search for gluino mediated stop/sbottom production in the 0 lepton channel with >=3 b-jets Multi-b jets enhance the sensitivity Various signal regions are optimized for a variety of pmssm scenarios Models with both stop (or sbottom) production and gluino production Models with gluino lighter than all squarks with gluino pair production only July 17, 2012 SUSY Experimental Results 28

29 Gluino Mediated Stop/Sbottom Search 3-body cascade decays 2-body cascade decays July 17, 2012 SUSY Experimental Results 29

30 Gluino Mediated Stop/Sbottom Search 2-body cascade decays 3-body cascade decays Limits on gluino mass ~1 TeV July 17, 2012 SUSY Experimental Results 30

31 Direct Stop Search From the hierarchy problem point of view, the scalar top should not be too heavy in order to cancel a large loop contribution from SM top. Strong reason to search for scalar top (stop) in dedicated searches! The search strategy varies depending on its mass Heavy stop [>m(top)] Signal: Leptonic or hadronic top decays with extra MET Light stop [<m(top)]: Signal: Top like decays via chargino. Low p T leptons, and subsystem mass below 2m(top) July 17, 2012 SUSY Experimental Results 31

32 ATLAS-CONF Direct Stop Search (1-lepton) Search for stops decaying to top quark, one top decays leptonically Selection Exactly 1 lepton >=4 jets with pt>80, 60, 40, 25 GeV >=1 b jet 130 GeV < m(jjj) < 205 GeV Define 5 different signal regions Background estimation 3 main BG: ttbar (l+jets), ttbar (dilepton), and W+jets simultaneous fit performed to three control regions & one signal region July 17, 2012 SUSY Experimental Results 32

33 Direct Stop Search (1-lepton) July 17, 2012 SUSY Experimental Results 33

34 ATLAS-CONF Direct Stop Search (0-Lepton) Search for stops decaying to top quark, both tops decay hadronically Expect 6 high pt jets Kinematic reconstruction of both tops is possible (no MET) Top background estimated using CR (l+jets) SM theory, jet energy scale and jet energy resolution are dominant uncertainties July 17, 2012 SUSY Experimental Results 34

35 Direct Stop Search (0-Lepton) SRA SRB July 17, 2012 SUSY Experimental Results 35

36 Combined Stop Exclusion July 17, 2012 SUSY Experimental Results 36

37 Combined Stop Exclusion Limits on stop mass up to 500 GeV! (Strongly depend on LSP mass) July 17, 2012 SUSY Experimental Results 37

38 Direct Gaugino Searches Mass limits on gluinos and squarks have been pushed higher and higher. Direct production of gaugino may be dominant SUSY production at the LHC. Typical signature: multiple leptons Searches with 2 and 3 leptons 2-leptons 3-leptons July 17, 2012 SUSY Experimental Results 38

39 ATLAS-CONF Direct Gaugino Searches w/ 3 Leptons Event Selection Background Reducible: ttbar+fake lepton Use efficiency / fake rate to obtain fake contribution in SR Irreducible: WZ Fit for signal and WZ in SR and a dedicated WZ-enhanced normalization region July 17, 2012 SUSY Experimental Results 39

40 ATLAS-CONF Searches with 2 Leptons Selection Backgrounds MT2 cut for a pair of of invisible decays Opposite sign (OS) ttbar, Z+jets, WW Extrapolate data control regions to SR by MC Same sign (SS) Fakes from QCD,W+jets Data driven Also direct slepton production July 17, 2012 SUSY Experimental Results 40

41 Direct Gaugino Searches 3 leptpons 2 leptpons 2 leptpons 1 st set of results/limits on direct EWKino/slepton production from LHC July 17, 2012 SUSY Experimental Results 41

42 Searches with Taus Motivation Measured relic density (Ω DM h 2 ~0.12) suggests either sufficient annihilation S. Martin co-annihilation In CMSSM, staus are typically the lightest sfermions At small m 0 stau and LSP could be almost mass degenerated Large co-annihilation cross section Cosmologically favored parameter region Some SUSY scenarios predict dominant decays of EWKinos in taus Signatures Typically 2 taus are produced 2-taus low pt, low ID efficiency 1 tau K. Matchev R. Remington July 17, 2012 SUSY Experimental Results 42

43 Searches with Taus Motivation Measured relic density (Ω DM h 2 ~0.12) suggests either sufficient annihilation S. Martin co-annihilation In CMSSM, staus are typically the lightest sfermions At small m 0 stau and LSP could be almost mass degenerated Large co-annihilation cross section Cosmologically favored parameter region Some SUSY scenarios predict dominant decays of EWKinos in taus Signatures Typically 2 taus are produced 2-taus low pt, low ID efficiency 1 tau K. Matchev R. Remington July 17, 2012 SUSY Experimental Results 43

44 CMS-SUS Searches with Taus Selection Tau ID for hadronically decaying taus 1-tau Exactly 1 tau: pt > 15 GeV, η < 2.1 No isolated light leptons, pt > 10 GeV HT>400/600, MHT>250/400 GeV 2-taus 2 jets: pt > 100 GeV, η < 3 Δϕ(MHT, jet2) > 0.5 >=2 taus: pt > 15 GeV, η < 2.1 ΔR(τ, jet1/2) > 0.3, ΔR(τ1, τ2) > 0.3 MHT > 250 GeV Backgrounds W ( τν) + jets / ttbar / Z ( νν) + jets / Drell-Yan ( ττ) + jets / QCD 1-tau: manly from real taus 2-taus: mainly from fake taus July 17, 2012 SUSY Experimental Results 44

45 Searches with Taus 1-tau CMSSM SMS Stau NLSP GMSB 1-tau and 2-tau searches are complementary 2-taus Gluino exclusinos up to ~800 GeV Gluino with masses below 860 GeV excluded July 17, 2012 SUSY Experimental Results 45

46 CMS-SUS Searches with Photons + MET Motivation Gauge mediated SUSY Large extra dimensions Bino-like NLSP Selection 1, 2 or more photons pt > 80 (40/25) GeV and eta < 1.4 At least 1 (2) jets with pt > 30 GeV and eta < 2.6 MET > 100 GeV Backgrounds QCD: jet-γ mis ID, jet mismeasurement W(eν)+γ: e-γ mis-id July 17, 2012 SUSY Experimental Results 46

47 Searches with Photons + MET Background estimation QCD - 2γ: Use kinematically similar control samples: QCD sample with 2 fake γ s Rescale γγ sample in MET < 20 GeV QCD - 1γ: Samples with 1 γ jet fake γ jet normalized to γ spectrum for photon Bino-like NLSP EWK backgrounds: Measure fake(e γ) probability Compare Z ee to Z eγ events for fake rate Inclusive electron spectrum scaled by f(e γ) to obtain EWK background Wino-like NLSP July 17, 2012 SUSY Experimental Results 47

48 Searches with Photons + MET Background estimation QCD - 2γ: Use kinematically similar control samples: QCD sample with 2 fake γ s Rescale γγ sample in MET < 20 GeV QCD - 1γ: Samples with 1 γ jet fake γ jet normalized to γ spectrum for photon Bino-like NLSP EWK backgrounds: Measure fake(e γ) probability Compare Z ee to Z eγ events for fake rate Inclusive electron spectrum scaled by f(e γ) to obtain EWK background Wino-like NLSP July 17, 2012 SUSY Experimental Results 48

49 CMS-SUS Stealth SUSY Motivation SUSY requires hidden sector to break supersymmetry Light hidden sector particles can mediate decays to many low pt objects Search in events with γγ+<=4 jets and large total energy S T Signatures Can include many b-jets, photons, γjj resonances, long-lived particles etc July 17, 2012 SUSY Experimental Results 49

50 ATLAS-CONF Long-Lived Particles Motivation Some SUSY scenarios predict long living gluino, stop, stau, slepton Signatures Very long lifetime. SUSY particles leave detector. Look for slow tracks High mass from time-of-flight M(Stau) > 310 GeV (tanβ=5-20) Pair-produced stable leptons > 297 GeV July 17, 2012 SUSY Experimental Results 50

51 CMSSM Summary July 17, 2012 SUSY Experimental Results 51

52 CMSSM Summary from CMS ICHEP 2012 July 17, 2012 SUSY Experimental Results 52

53 CMSSM Summary from CMS Fall 2011 ICHEP 2012 July 17, 2012 SUSY Experimental Results 53

54 CMSSM Summary from CMS Moriond 2011 Fall 2011 ICHEP 2012 July 17, 2012 SUSY Experimental Results 54

55 CMSSM Summary from CMS Moriond 2011 Fall 2011 Before LHC data taking ICHEP 2012 July 17, 2012 SUSY Experimental Results 55

56 CMSSM Summary from CMS Moriond 2011 Fall 2011 Before LHC data taking ICHEP 2012 m h = 125 GeV? July 17, 2012 SUSY Experimental Results 56

57 CMSSM Summary from CMS Moriond 2011 Fall 2011 Before LHC data taking ICHEP 2012 m h = 125 GeV? m 1/2 >~ 2 TeV & m(gluino)=4-5 TeV Very fine-tuned model Good that LHC experiments are using simplified model to map out the possible new physics phase space July 17, 2012 SUSY Experimental Results 57

58 ATLAS SUSY Search Summary 1 TeV July 17, 2012 SUSY Experimental Results 58

59 ATLAS SUSY Search Summary Many SUSY limits reaching/approaching 1 TeV. 1 TeV July 17, 2012 SUSY Experimental Results 59

60 ATLAS SUSY Search Summary Many SUSY limits reaching/approaching 1 TeV. Direct stop and EWKino limits just started to be placed 1 TeV July 17, 2012 SUSY Experimental Results 60

61 CMS Search Summary with SMS Hadronic Searches Leptonic Searches 3 bars for different intermediate χ masses Limits much milder for compressed spectra! July 17, 2012 SUSY Experimental Results 61

62 Summary July 17, 2012 SUSY Experimental Results 62

63 Summary ATLAS and CMS have presented a beautiful set of new results on SUSY searches at ICHEP July 17, 2012 SUSY Experimental Results 63

64 Summary ATLAS and CMS have presented a beautiful set of new results on SUSY searches at ICHEP Many new inclusive searches all hadronic, leptonic, w/ b-tags, w/ photons, w/ taus, etc, etc. Searches started to place limits on direct stop & EWKino production No convincing sign of SUSY signals yet. Where is SUSY hiding? July 17, 2012 SUSY Experimental Results 64

65 Summary ATLAS and CMS have presented a beautiful set of new results on SUSY searches at ICHEP Many new inclusive searches all hadronic, leptonic, w/ b-tags, w/ photons, w/ taus, etc, etc. Searches started to place limits on direct stop & EWKino production No convincing sign of SUSY signals yet. Where is SUSY hiding? We have more to cover this year! July 17, 2012 SUSY Experimental Results 65

66 Summary ATLAS and CMS have presented a beautiful set of new results on SUSY searches at ICHEP Many new inclusive searches all hadronic, leptonic, w/ b-tags, w/ photons, w/ taus, etc, etc. Searches started to place limits on direct stop & EWKino production No convincing sign of SUSY signals yet. Where is SUSY hiding? We have more to cover this year! Improved sensitivities in 2012 with higher s and more data Only a handful of searches with 2012 data have made ICHEP. A lot more data will come by the end of exntended data taking period (pp data taking until Dec 17. ~20 fb -1?) Search methods have advanced through 2011 analyses, &still evolving. Variety of robust searches Sensitivities to stop, EWKino are rapidly ramping up. July 17, 2012 SUSY Experimental Results 66

67 Summary ATLAS and CMS have presented a beautiful set of new results on SUSY searches at ICHEP Many new inclusive searches all hadronic, leptonic, w/ b-tags, w/ photons, w/ taus, etc, etc. Searches started to place limits on direct stop & EWKino production No convincing sign of SUSY signals yet. Where is SUSY hiding? We have more to cover this year! Improved sensitivities in 2012 with higher s and more data Only a handful of searches with 2012 data have made ICHEP. A lot more data will come by the end of exntended data taking period (pp data taking until Dec 17. ~20 fb -1?) Search methods have advanced through 2011 analyses, &still evolving. Variety of robust searches Sensitivities to stop, EWKino are rapidly ramping up. The SUSY is the next discovery frontier! July 17, 2012 SUSY Experimental Results 67

68 Backup

69 LHC Performance 2012 certified data for physics 5.19 fb-1 (85%) Peak luminosity in 2012: ~ 6.8 x10 33 cm -2 s -1 Many thanks to the LHC teams and the many others who made this possible! July 17, 2012 SUSY Experimental Results 69

70 Pileup July 17, 2012 SUSY Experimental Results 70

71 CMS and ATLAS Detectors CMS Length : ~22 m Diameter : ~14 m Weight : ~ 12,500 tons Solenoid : 4 T Fe yoke Compact and modular Excellent EM Calorimeter ATLAS Length : ~45 m Diameter : ~24 m Weight : ~ 7,000 tons Electronic channels : ~ 10 8 Solenoid : 2 T Air-core toroids Excellent Standalone Muon Detector July 17, 2012 SUSY Experimental Results 71

72 Particle CMS The PFlow algorithm is designed to: Reconstruct & identify all particles: γ, e, μ, charged & neutral hadrons, pileup, and converted photons & nuclear interactions Use a combination of all CMS subdetectors to get the best estimates of energy, direction, particle ID July 17, 2012 SUSY Experimental Results 72

73 Particle CMS The PFlow algorithm is designed to: Reconstruct & identify all particles: γ, e, μ, charged & neutral hadrons, pileup, and converted photons & nuclear interactions Use a combination of all CMS subdetectors to get the best estimates of energy, direction, particle ID 1. Associate hits within each detector HCAL Clusters ECAL Clusters Tracks July 17, 2012 SUSY Experimental Results 73

74 Particle CMS The PFlow algorithm is designed to: Reconstruct & identify all particles: γ, e, μ, charged & neutral hadrons, pileup, and converted photons & nuclear interactions Use a combination of all CMS subdetectors to get the best estimates of energy, direction, particle ID 1. Associate hits within each detector 2. Link across detectors HCAL Clusters ECAL Clusters Tracks July 17, 2012 SUSY Experimental Results 74

75 Particle CMS The PFlow algorithm is designed to: Reconstruct & identify all particles: γ, e, μ, charged & neutral hadrons, pileup, and converted photons & nuclear interactions Use a combination of all CMS subdetectors to get the best estimates of energy, direction, particle ID 1. Associate hits within each detector 2. Link across detectors 3. Particle ID and separation Charged Hadrons neutral hadron HCAL Clusters ECAL Clusters Electron Tracks July 17, 2012 SUSY Experimental Results 75

76 Particle CMS The PFlow algorithm is designed to: Reconstruct & identify all particles: γ, e, μ, charged & neutral hadrons, pileup, and converted photons & nuclear interactions Use a combination of all CMS subdetectors to get the best estimates of energy, direction, particle ID 1. Associate hits within each detector 2. Link across detectors 3. Particle ID and separation Used in most CMS searches Charged Hadrons neutral hadron HCAL Clusters ECAL Clusters Electron Tracks July 17, 2012 SUSY Experimental Results 76

77 MET with Pileups Missing ET can be sensitive to pileup (additional pp) interactions Average pileup ~10 in Doubled in Both CMS and ATLAS have good modeling of pileup in simulation and also reducing pileup effects 2011 data Number of reconstructed primary vertices Irene Vichou s talk Calor 2012 July 17, 2012 SUSY Experimental Results 77

78 CMSSM / msugra Inclusive SUSY results have been conventionally shown in the context of constrained MSSM / msugra CMSSM has only 5 parameters: Universal scalar mass m 0 S. Martin Universal gaugino mass m 1/2 Universal trilinear coupling A 0 Ratio of 2 Higgs doublet VEV tanβ Sign of the Higgisino mixing parameter sgn(μ) Very predictive; however, the universality constraints result in significant restrictions on possible SUSY particle mass spectra ~Now Just after the Bing Band July 17, 2012 SUSY Experimental Results

79 Razor Razor search designed to discriminate heavy pair production kinematically from SM backgrounds No assumptions on MET or details of decay chain CM frame M R definition: signal Laboratory Frame Two massive particles produced at rest (e.g. q 1 ) M p j = 1, Mq ~ M 1,2 χ1,2 = 2 M~ q 1,2 0 χ 1 q 2 j 1 0 χ 2 j 2 Boost 0 χ 1 j 2 0 χ 2 j 1 R frame equalizes 3-momentum of the two jets = CM frame if no ISR M R = 2 p = ˆs M R peaks for the signal at the mass scale of the heavy particle, M D July 17, 2012 SUSY Experimental Results 79

80 Razor Razor search designed to discriminate heavy pair production kinematically from SM backgrounds No assumptions on Met or details of decay chain CM frame M R definition: multijet background Laboratory Frame Two jets back to back j 1 j 1 j 2 Boost j 2 R frame equalizes 3-momentum of the two jets = CM frame if no ISR M R 2 p = ˆs = M R falls steeply July 17, 2012 SUSY Experimental Results 80

81 Transverse M R has a kinematic edge of M D ) ( ) ( ) ( 2 2 j j j z j z j z j j z j R j R j R E E p p p E p E p p M = = Razor July 17, 2012 SUSY Experimental Results 81 For the signal, M R is a measure of the mass of the heavy particle and peaks at the scale of the production Maximum of scalar sum of the p T of the two jets is M D The maximum value of ME T is also M D Real life: multi-jet events define two hemispheres and combine jets into two mega-jets (force di-jet topology) 2 ).( ) ( j T j T miss T j T j T miss T R T p p E p p E M + + = R R T M M R M R peaks at mass scale M D Razor (R) has a kinematic edge of 1, peaks at 0.5 Razor used to separate signal from background

82 R and M R Properties CMS-SUS July 17, 2012 SUSY Experimental Results 82

83 Box Definitions and Fits Minimum R 2 and M R set by trigger requirements Find state BOX classification based on lepton ID Extended and unbinned maximum likelihood fit performed in 2D R 2 -M R plane independently in each BOX Background functionally extrapolated to signal region July 17, 2012 SUSY Experimental Results 83

84 Results 1D projections of 2D ML Fit HAD Box Observations consistent with SM expectations Model independent results showing data/prediction compatibility R 2 M R July 17, 2012 SUSY Experimental Results 84

85 R-parity Violating SUSY Most SUSY models assume R-parity [=(-1) 3(B-L)+2S ] conservation Dark matter candidate Makes MSSM more predictive Prevent proton decays (but only simultaneous violation of lepton and baryon numbers are forbidden) Generic analysis sensitive to many SUSY models Neutral sneutrino decaying to e μ pair Signatures Multileptons eμ resonances eμ continuum LFV t-channel exchange of scalar quark July 17, 2012 SUSY Experimental Results 85

86 ATLAS-CONF Multilepton Search Selection SR1: At least 4 leptons with MET>50 GeV SR2: SR1 + m ll -m Z >10 GeV for each l+l- pair For tanβ<40, gluino masses below 1770 GeV are excluded. July 17, 2012 SUSY Experimental Results 86