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Introduction to Supersymmetry

S. Muanza, CPPM Marseille, CNRS-IN2P3. Introduction to Supersymmetry. PART II Experimental Searches. LHC. Personal Bias: I’ll present results from the ATLAS experiment. LHC - Experiments -. 3 Experiments can carry SUSY searches: Direct: ATLAS & CMS Indirect: LHCb. LHC

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Introduction to Supersymmetry

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  1. S. Muanza, CPPM Marseille, CNRS-IN2P3 Introduction to Supersymmetry "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  2. PART II Experimental Searches "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  3. LHC Personal Bias: I’ll present results from the ATLAS experiment "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  4. LHC - Experiments - • 3 Experiments can carry SUSY searches: • Direct: ATLAS & CMS • Indirect: LHCb "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  5. LHC - Nominal Features - 25 ns Event rate: N = L x (pp)  109 interactions/s Mostly soft ( low pT ) events Interesting hard (high-pT ) events are rare "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  6. LHC - 2012 Integrated Luminosity - eDAQ = 95.3% Counting rate from L detectors "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  7. Data Taking Conditions Evolution of the instantaneous luminosity Evolution of the nber of p bunches <Nber> of collisions per bunch crossing A Multiple pp Collision "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  8. "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  9. Analyses: Higgs Searches - Trigger: On-Line Selection - "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  10. Production Mechanisms LO Feynman Diagrams Cross Sections Unique opportunity to measure the top Yukawa coupling! "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  11. Decay Modes LO Feynman Diagrams Branching Ratios "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  12. Search Topologies - 2 Examples - 2 photons 4 charged leptons Signal Background Irreducible: Reducible: Z+bb, tt+jets "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  13. Analyses - Offline Selection - • Events read from tape • Improved signal vs background separation "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  14. ATLAS Candidates (1) Photon candidates are unconverted. Event number: 56662314 Run: 203779 at sqrt(s) = 8 TeV g1: pT = 62.2 GeV and h = 0.39 g2: pT = 55.5 GeV and h = 1.18 M(gg) = 126.9 GeV "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  15. ATLAS Candidates (2) EventNumber: 71902630 RunNumber: 204769 M(4m)=125.1 GeV M12=86.3 GeV, M34=31.6 GeV m1: pT=36.1 GeV, h=1.29, f=1.33 m2: pT=47.5 GeV, h=0.69, f=-1.65 m3: pT=26.4 GeV, h=0.47, f=-2.51 m4: pT=71.7 GeV, h=1.85, f=1.65 "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  16. CMS Candidates "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  17. Recent CMS Results - HCP2012, 12-16 Nov 2012 - Confirmation of the dicovery Parity Signal strength by channel "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  18. SUSY Interpretation of a Higgs Signal (1) • Modified Couplings: • Decoupling Limit: • Additional contribution to loops: • could make differences in h0 BRs and explain the currently observed tensions between • the decay channels => h0 is light and has SM-like couplings Realized in practice when: "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  19. SUSY Interpretation of a Higgs Signal (1) • Large Mixing in Stop Sector: Max. Mixing: "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  20. SUSY Searches - Production Mechanisms (1) - • How are these Sparticles produced? • Gluino pairs: • Squark pairs: • Gluino+Squark pairs: • Chargino pairs: • Chargino+Neutralino pairs: "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  21. SUSY Searches - Production Mechanisms (2) - • What are the cross sections? • Obtained with Prospino (include NLO-QCD corrections) • They determine which Sparticles are accessible and the hierarchy in their search "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  22. SUSY Searches - Decay Modes - • How do these Sparticles decay? • Squarks: • Gluinos: • Search topologies are chosen wrt to some decay chains • In RPC searches the phase space is limited by a DM "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  23. SUSY Searches - Decay Modes - • What are the serach topologies? "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  24. Analysis Tools - Kinematic Variables - • Pseudo-rapidity: • Angular distance in space: • Missing Transverse Energy: • Total Transverse Energy: • It’s a scalar sum • : • Lower bound helps reduce from jets mis-measurements "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  25. Analysis Tools - Anti-kT Jets - • Definition: It’s a recombination algorithm • Properties: • it is IR-safe • it can easily be implemented in theoretical or experimental analyses • it can be defined at any order of the perturbation theory • Description: • Recombines successively closest pairs area fluctuates and depends on pT area fluctuates, depends less on pT constant area (circular jets) • Implementation: http://www.fastjet.fr "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  26. Analysis Tools - Kinematic Variables - • Effective Mass: • sensitive to • Stransverse mass: • lower bound on mass of particle decaying semi-invisibly • Contransverse mass: • useful for identical parent particles decay semi-invisibly HT invisible visible where (usual transverse mass) "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  27. SUSY  Multijets+mET (1) L=1.04 fb-1 • Dataset: • 2011 p+p collisions • Trigger: • LVL1: multijets • HLT: 5j55 or 6j45 • Performance: e=99% • Data Quality: • Remove bad L blocks • Remove evts w/ bad jets • Reject evts w/ cosmics or noise • Object ID: • Jets: • anti-kT, DR=0.4 • pT > 20 GeV • |h|<2.5 • e: medium, pT > 20 GeV, |h|<2.47 • e isolation: HT(tracks) (DR=0.2)<10% pT(e) • m: matched, pT > 20 GeV, |h|<2.4 • m isolation: HT(tracks) (DR=0.2)<1.8GeV • Veto isolated e or m "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  28. SUSY  Jets+mET (3) • Main Background Processes: • Z+jets: especially Z(nn)+jets • W+jets: especially W(tn)+jets or W(e/mn)+jets w/ missed e/m • QCD multijet • Background Estimation: • Evaluate each process in a « Control Region » (5 CRs x 5 SRs) • Extrapolate the CR to SR using transfer factors: • Estimate Signal Sensitivity: • Profile log-likelihood fit (with correlated systematic uncertainties and CRs cross-contamination) "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  29. SUSY  Jets+mET (3) "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  30. SUSY  Jets+mET (3) "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  31. SUSY  Jets+mET (3) "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  32. SUSY  Jets+mET (3) "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  33. SUSY  Jets+mET (3) "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  34. SUSY  Jets+mET (3) Event w/ highest meff found 5 jets with pt > 40 GeV: pt = 528, 418, 233, 171, 42 GeV met = 460 GeV meff =1810 GeV (4 leading jets) "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  35. SUSY  Jets+mET (3) "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  36. SUSY  Jets+mET (3) "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  37. SUSY Searches - ATLAS Summary - "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  38. II. ILC "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  39. Main Features structures the beam bunches • Advantages: • Very clean and flexible environment: • tuneable E: • polarized beams: • low rate: 15-30 kHz • sensitivity to virtual effects • Drawbacks: • large gg background (0.1 evt / bunch X) • 10% evts w/ • monitor accolinearity of Bhabha’s • to estimate accelarating niobium cavities (Phase I: ~500 fb-1) (Upgrade  Phase II) "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  40. Detector Concepts (1) B=4 T Large Detector Concept B=5 T Silicon Dectector "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  41. Detector Concepts (2) B=3.5 T Global Detector Concept • « Triggerless Mode » Collider: • Low rate enables: • No hardware trigger • Just a software-based • trigger for loose filtering • Typical Requirements: • Inner Tracking: • Vertex Detector: • Outer Tracking: • Calorimetry: • EM: • Jets: "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  42. SUSY Benchmark • SPS1a: • Old SUSY benchmark in the bulk region • Outside the recent allowed region from WMAP "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  43. SUSY Measurements "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  44. Thresholds & Edges Measurements L=200 fb-1 Beam Polarization "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  45. Threshold Scans L=100 fb-1 Sharp production thresholds => E scan gives good sensitivity M(FS) "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  46. mSUGRA Fit SFitter "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  47. III. Indirect Accelerator Constraints • Hereafter I describe some virtual effects • measured at accelerators that indirectly • constrain SUSY: • am =1/2(g-2)m • bsg (not covered today) • Bsm+m-,… "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  48. Bsm+m- (1) • In SM Bs+- is suppressed (need FCNC) SM predicts • SUSY can enhance BR by 1 order of magnitude Ref: M. Blanke et al., JHEP 0610 (2006) 003 A key early measurement for LHC "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  49. Bsm+m- (2) L=3.7 fb-1 L=6.1 fb-1 CDF Result: No excess seen Aug 2009 D0 Result: No excess seen Jun 2010 "Introduction to Supersymmetry", L. Vacavant & S. Muanza

  50. Bsm+m- (3) • ATLAS & CMS: • |hm|<2.5, L=1032-33 cm-2s-1 • Single & di-muon triggers • LHCb: • 1.9<|hm|<2.5, L=2x1032 cm-2s-1 • Low pT trigger (sensitivity to sbb 2.3 larger than ATLAS & CMS) • Evt Selection: • based upon several variables, including Mmm • mass resolutions: 90 MeV (ATLAS), 53 MeV (CMS), 22 MeV (LHCb) CMS: 1fb-1 (incl. syst.) "Introduction to Supersymmetry", L. Vacavant & S. Muanza

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