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Higgs, SUSY and non-SUSY BSM in ATLAS

18th International Conference on Supersymmetry and Unification of Fundamental Interaction August 23-28, 2010 Bonn, Germany. Higgs, SUSY and non-SUSY BSM in ATLAS. Johannes Haller (Universität Hamburg/DESY) on behalf of the ATLAS collaboration. ATLAS Detector.

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Higgs, SUSY and non-SUSY BSM in ATLAS

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  1. 18th International Conference on Supersymmetry and Unification of Fundamental Interaction August 23-28, 2010 Bonn, Germany Higgs, SUSY and non-SUSY BSM in ATLAS Johannes Haller (Universität Hamburg/DESY) on behalf of the ATLAS collaboration

  2. ATLAS Detector L ~ 46 m,  ~ 22 m, 7000 tons ~108 electronic channels Inner Tracker (||<2.5, B=2T): Si Pixels, Si strips, Trans. Rad. Det. Precise tracking and vertexing, e/ separation, momentum resolution: /pT ~ 0.04% pT (GeV)  1.5% EM calorimeter: Pb-LAr Accordion, e/ trigger, id. and meas., energy res.: /E ~ 10%/E  0.7% HAD calorimetry(||<5): Fe/scintillator Tiles (cen), Cu/W-LAr (fwd). trigger and meas. of jets and ET,miss, energy res.:/E ~ 50%/E  3% Muon Spectrometer:air-core toroids with gas-based muon chambers. trigger and meas. with momentum resolution < 10% up to E ~ 1 TeV Trigger system: 3-levels reducing the IA rate from 40 MHz to ~200 Hz Higgs, SUSY and non-SUSY BSM in ATLAS

  3. Reality after ~15 years of preparation L ~ 46 m,  ~ 22 m, 7000 tons ~108 electronic channels Muon chambers Toroid coils Calorimeters Higgs, SUSY and non-SUSY BSM in ATLAS

  4. LHC status and plans • status: LHC delivers √s=7 TeV pp collisions and ATLAS records them • int. luminosity so far: ∫Ldt~1.8 pb-1 • short term: pp physics till 1. Nov • aim to get to L=1032cm-2s-1 • 432+432 bunches in trains • 10 pb-1/day, ∫Ldt ~ 100 pb-1 • followed by ion run/technical stop (end 2010/start 2011) • this talk: • BSM/SUSY physics results with current data set • example physics prospects with future √s=7 TeV data • mid term: ∫Ldt=1fb-1 by end of 2011 • followed by ~year of shutdown (2012) • repair splices → √s=14 TeV • long term: 10 fb-1 at √s=14TeV by end of 2014 Higgs, SUSY and non-SUSY BSM in ATLAS

  5. The LHC physics landscape 7 TeV • LHC detectors are looking for needles in the haystacks • rare processes hiding in overwhelming background of “bread and butter” physics • rates at 7 TeV and 1032 cm-2s-1 integrated luminosity/time • lumi today: ~1.8 pb-1 (less analysed) • study of SM bgr and detector behavior • starting to enter region with BSM sensitivity • 1000 times more expected by end 2011 Higgs, SUSY and non-SUSY BSM in ATLAS

  6. New Physics in initial running period? • current best competitor: Tevatron • typically ~5fb-1 with √s=1.96 TeV • disadvantage: loss in statistics: • ∫Ldt=(5-10) fb-1→ ∫Ldt=(0.1-1) fb-1 • advantage: gain in cms energy • √s=2 TeV → √s=7 TeV • gain depends on initial state (gg or qq) and required invariant mass (MX) • e.g. HWW at 160 GeV, gains factor ~15 (gg dominated) • e.g. 1 TeV Z’ (qq) gains factor ~100 • (to be considered in full analysis: signal efficiencies, backgrounds etc.) WJ Stirling • plenty of potential for new physics surprises even in 2010 run Higgs, SUSY and non-SUSY BSM in ATLAS

  7. General ATLAS performance • detector working very well • data taking efficiency > 95% • detector performance → A Belloni • trigger performance • L1 trigger rates scale nicely • L1 trigger efficiencies for electrons, jets, muon, ET,miss high and steep Higgs/SUSY/BSM events are read out and recorded efficiently L1 e trigger efficiency L1 jet trigger efficiency Higgs, SUSY and non-SUSY BSM in ATLAS

  8. Search for New Physics in dijet final states QCD (mjj~1TeV) q* (1TeV) • sensitivity to BSM in dijet final states already with small data sets • event distributions of QCD (fwd jets) and BSM (central jets) differ • search for dijet-resonances • event selection: (315 nb-1) • jet1: pT> 80 GeV; jet2: pT> 30 GeV • |ηj1|<2.5; |ηj2|<2.5 and |Δη|<1.3 • scan mjj spectrum for resonances • resolution: mjj=200 GeV (1TeV): 13 % (6%) • data described by smooth fit function • many tests → p-values always > 50% no evidence for a resonance See talk by Frederik Ruehr [subm. to PRL, arXiv:1008:2461] Higgs, SUSY and non-SUSY BSM in ATLAS

  9. Search for New Physics in dijet final states mj1j2 =1.77 TeV pT (j1)= 1120 GeV pT (j2)= 480 GeV pT (j3)= 155 GeV pT (j4)= 95 GeV Higgs, SUSY and non-SUSY BSM in ATLAS

  10. Search for New Physics in dijet final states • 95% CL exclusion limits • excited-quark model considered • IA described by eff. Lagrangian: • Λ: compositeness scale (here: Λ=mq*) • f, f’, fs: coupl. parameters (f=f’=fs=1) • fs≠0: qg-fusion production; dijets decays • excluded: 400 GeV < mq* < 1260 GeV • compare CDF: 260 GeV < mq* < 870 GeV [Phys. Rev. D79 112002 (2009)] • first published BSM result from LHC [subm. to PRL, arXiv:1008:2461] Higgs, SUSY and non-SUSY BSM in ATLAS

  11. Search for New Physics in dijet final states • search for non-resonant BSM effects at high mjj • study directly the angular distribution of jets • event selection (~61nb-1): QCD: rather forward jets (t-channel) New Physics: isotropic, widely separated jets • jet1: pT> 60 GeV; jet2: pT> 30 GeV • |ηj1|<2.8; |ηj2|<2.8; • |y1+y2|<1.5 [ATLAS-CONF-2010-074] • two observables: Higgs, SUSY and non-SUSY BSM in ATLAS

  12. Search for New Physics in dijet final states • data well described by SM prediction (LO Pythia) • limits in qqqq contact interaction scenario • 95 % CL exclusion limits: • limit ~ measured mjj range: limit not physical, rather demonstrates current sensitivity • compare with D0: L>2.8 TeV [PRL 103:191803,2009] 520 GeV <mjj < 680 GeV [ATLAS-CONF-2010-074] χ-spectrum: Λ>930 GeV η-ratio: Λ>760 GeV Higgs, SUSY and non-SUSY BSM in ATLAS

  13. Search in high multiplicity final states at high minv • model independent search in final states with high multiplicity • check: Minv of several (n≥3) high pT objects • use: central jets (pT>40 GeV), e/g (pT>20 GeV), μ (pT>20 GeV) • control region: normalization of MC to data • ΣpT > 300 GeV and 300 GeV < Minv < 800 GeV • signal region: look for deviations • ΣpT > 700 GeV and Minv > 800 GeV • no deviation from SM  exclusion limits • upper limit (95%CL) on σ*acc. = 0.34 nb control region [ATLAS-CONF-2010-088] signal region Higgs, SUSY and non-SUSY BSM in ATLAS

  14. Neutral gauge bosons in ATLAS see talk by Kristina Strandberg • many BSM models: new neutral bosons (Z’) • here: SM-like model (SSM) • current best limit: CDF: mZ’ > 1 TeV (95%CL) • characteristics at the LHC with √s=7TeV • clear signatures : Z’→ l+l- (e or μ) • σ*acc (ee+μμ): ~120 fb (mZ’=1TeV) electron channel [ATLAS-CONF-2010-076] • event selection: • e channel: 2 e cand. with ET> 20 GeV, |η|<2.5 • μchannel: 2 μ cand. with pT >15 GeV, |η|<2.4 • opposite charges • mee and mμμ distribution described by SM • σZ→ll~0.96nb, QCD bgr: ~1% • “observation of SM Z0→ll at LHC” muon channel Higgs, SUSY and non-SUSY BSM in ATLAS

  15. Neutral gauge bosons in ATLAS • Z→ee candidate recorded on 9th May 2010 ET (e+) = 40 GeV ET (e-) = 45 GeV η(e+) = -0.38 η(e-) = 0.21 mee = 89 GeV Higgs, SUSY and non-SUSY BSM in ATLAS

  16. Neutral gauge bosons in ATLAS • luminosity needed for … … an exclusion at 95% CL: … a Z’ discovery: [ATL-PHYS-PUB-2010-007] modified frequentist approach • for mZ’= 1.0 TeV already with ~100 pb-1 (early 2011) 100 pb-1(early 2011): ~1300 GeV 1 fb-1 (end 2011): ~1800 GeV It is getting interesting soon ! Higgs, SUSY and non-SUSY BSM in ATLAS

  17. Search for heavy charged gauge bosons (W’) • many BSM models: W’ • again: SM-like model (SSM), currently: DØ: mW’ > 1TeV (95% CL) • characteristics at the LHC • signature: W’→ lνl, crucial: pT reconstr. of energetic leptons • σ*acc. (eνe): ~300 fb (mW’=1TeV) electron channel • dedicated W’ search in e-channel (317nb-1) • isolated, central electron candidate with pT>20 GeV • ET,miss> 25 GeV [ATLAS-CONF-2010-089] • no excess at high mT • main background: SM W production →“observation of SM W± l±ν at LHC” Higgs, SUSY and non-SUSY BSM in ATLAS

  18. Search for heavy charged gauge bosons (W/W’) • W→eν candidate event recorded on 5th April 2010 ET (e+) = 34 GeV η(e+) = -0.42 ET,miss = 26 GeV MT = 57 GeV Higgs, SUSY and non-SUSY BSM in ATLAS

  19. Search for heavy charged gauge bosons (W/W’) • luminosity needed for … • 95% CL exclusion limit: • 317 nb-1, e-channel only … a W’ discovery: [ATLAS-CONF-2010-089, ATL-PHYS-PUB-2010-007] • excluded: mW’ < 465 GeV • compare to Tevatron: mW’ <1 TeV • expected (e+μ): • for mW’=1 TeV already with ~10-20 pb-1 (fall this year) • 20 pb-1(fall 2010): ~1200 GeV • 100 pb-1(early 2011): ~1600 GeV • 1 fb-1 (end 2011): ~2300 GeV We are rapidly accessing unexplored regions Higgs, SUSY and non-SUSY BSM in ATLAS

  20. Search for Supersymmetry • production at the LHC: strongly interacting particles • depending on masses: large cross-sections (αs) • final states at the LHC: model-dependent • in general: long decay chains • hadronic jets, (b-jets) • ET,miss (LSP RPC CDM) • (charged leptons) • all detector components needed • strategy: inclusive searches • no resonances  description of SM bgr in tails crucial • current best mSugra limits: Tevatron: • current LHC dataset: no sensitivity to unexplored regions yet (mSUGRA) • SUSY analyses rather background studies at this stage • loosen cuts → check control regions → compare with background MC → check SUSY-sensitive variables → for fun: also look into the signal region compare with SU4, “low mass point” • σ(NLO, Prospino) = 59.9 pb • m(squarks, gluinos) ~ 410-420 GeV • m0=200 GeV, m1/2=160 GeV, A0=–400 GeV, tanβ=10 and μ>0 Higgs, SUSY and non-SUSY BSM in ATLAS

  21. SUSY: data results in “jets + ET,miss” See parallel talk by Renaud Bruneliere • highest discovery potential: in “jets+ET,miss+0lept” channel • final selection: • ET,miss>40GeV, ΔΦ(ji, ET,miss)>0.2 • ET,miss/Meff> 0.3-0.2 • pre-selection: (~70nb-1,L1 jet trigger) • =1, ≥2, ≥3, ≥4 jets with pT>70 (30) GeV two jet channel: three jet channel: four jet channel: [ATLAS-CONF-2010-065] • normalization of LO Pythia MC to data: 2-jet channel after presel • nice description of ET,miss and Meff (and many more) shapes by MC (QCD) • signal region: 4 events, expected: 6.6±3 (mainly VB +jets) • three (four)-jet channel • after pre-selection: QCD bgr reasonably described by MC • final selection: 0 (1) event in data; expected: 1.9 ± 0.9 (1.0±0.6) • summary: in all channels agreement between data and MC • SM background under control ! • (but mSugra signal still too small) Higgs, SUSY and non-SUSY BSM in ATLAS

  22. SUSY: data results in “jets + ET,miss + lepton(s)” See parallel talk by Yousuke Kataoka • slightly different selection to select sufficient statistics • 70 nb-1, L1 muon or electron trigger • one-lepton channel: • =1 lepton (e or μ) with pT>20 GeV • ≥two jets with pT>30 GeV • signal effi for SU4 : ~ 5% • QCD (Pythia) and W+jets (Alpgen) expectation normalized to data in dedicated control regions muon channel: • after cut: ET,miss > 30 GeV & mT> 100 GeV : electron channel: [ATLAS-CONF-2010-066] •  SM background to SUSY searches under control Higgs, SUSY and non-SUSY BSM in ATLAS

  23. SUSY: data results in “b-jets + ET,miss” See parallel talk by Mark Hodgkinson • SUSY signals typically rich in b quarks • mixing chiral states (tanb)  small masses of 3rd generation sfermions • b-tagging algorithm: explicitly reconstruct secondary vertices • decay length significance: L/s > 6 • εb-tagging ~ O(50%) data and MB MC [ATLAS-CONF-2010-042, ATLAS-CONF-2010-079] • MC normalization performed in dedicated control regions: • 0-lepton channels: • ≥2-j (70,30), ET,miss/√ΣET > 2 √GeV • region dominated by QCD multijet • good agreement over entire range • 1-lepton channels: • ≥2-j (70,30), ET,miss/√ΣET > 2 √GeV, MT<40GeV → non-QCD bgr small Higgs, SUSY and non-SUSY BSM in ATLAS

  24. SUSY: data results in “b-jets + ET,miss” • event selection (305 nb-1): • always: ET,miss/√ΣET > 2 √GeV, at least one b-jet • channels: “≥2 jets (pT>70, pT>30)”, “2 jets (pT>30,pT> 30) + ≥1 lepton (pT>20)” 1jet + 1b-jet 1μ+ 1jet + 1b-jet [ATLAS-CONF-2010-079] • reasonable agreement data – MC • b-tagging promising tool • SM background under control • no sensitivity to mSugra signal yet 1e+ 1jet + 1b-jet Higgs, SUSY and non-SUSY BSM in ATLAS

  25. SUSY: prospects for the √s=7 TeV run • new sensitivity study for √s=7 TeV • many inclusive channels • example: “ET,miss + 4 jets + 0 lept” • best discovery reach • dominant bgr: top, W [ATL-PHYS-PUB-2010-010] • discovery reach in mSUGRA plane • expect bgr (from data) uncert. ~50 % • 5σ: squarks and gluinos up to ~700 GeV • expect exclusion beyond Tevatron • with ~O(10pb-1) Higgs, SUSY and non-SUSY BSM in ATLAS

  26. SM Higgs: prospects for the √s=7 TeV run • new sensitivity study for √s=7 TeV • cross section (NLO used) scaling from full simulation studies at 10/14 TeV • change 14→7 TeV: gg→H: 28%, W+Jets: 48%, ttbar: 18%,WW: 38% • highest production: gg→H • ~10-20x higher than Tevatron • clean signatures: g, WW, ZZ [ATL-PHYS-PUB-2010-009] Higgs, SUSY and non-SUSY BSM in ATLAS

  27. SM Higgs: H→WW channel (7 TeV, 1fb-1) • most prolific channel at intermediate MH • signature: 2 l at high pT and large ET,miss • selection in “H+0jet”, “H+1jet”, “H+2jet” • main background: SM WW production • qq dominated • parton luminosities →better S/B compared to Tevatron • LHC competitive with small data sets • expected 95%CL excluded regions: • first exclusion already with 250 pb-1 • 1fb-1: exclude 145 GeV <MH< 182 GeV • 5σ discovery would need ∫Ldt>2.3 fb-1 number of exp. events after selection: [ATL-PHYS-PUB-2010-009] Higgs, SUSY and non-SUSY BSM in ATLAS

  28. SM Higgs: H→ZZ(*) channel (7 TeV, 1fb-1) • “golden channel” important at high MH • clean 4 lepton signature • narrow minv peak above smooth bgr (irreducible ZZ(*)→4l) • width of the Higgs peak • MH<220 GeV: detector mass resolution crucial → apply MZ constraint • MH>220 GeV: detector mass resolution not crucial since ΓH>Γexp • expected exclusion limits (95% CL) • no exclusion possible for any mass • highest sensitivity at MH~200 GeV • note: results for large MH depend on ΓH prediction → result only valid in SM [ATL-PHYS-PUB-2010-009] 2.5 Higgs, SUSY and non-SUSY BSM in ATLAS

  29. SM Higgs: H→ channel (7 TeV, 1fb-1) • channel important at small MH: • low BR (~0.2%), but robust signal • early data: inclusive analysis strategy • only discriminating variable: m • backgrounds • irreducible • crucial: mgg resolution (~1.1%) • reducible: g-jet, multijets • critical to reach jet rejection O(5000) • π0: high granular ATLAS calorimeter • expected exclusion limit (7 TeV, 1fb-1) • (σ*BR)95/SM = 4.4 – 5.8 • no exclusion possible, but significantly better than current Tevatron limits (~20) Born Brem Box [ATL-PHYS-PUB-2010-009] Higgs, SUSY and non-SUSY BSM in ATLAS

  30. SM Higgs: expected combined sensitivity • combination of gg, ZZ and WW channels • shown mass range: limit dominated by H→WW channel • low mass region (MH<130 GeV): gg channel contributes • high mass (MH>200 GeV): limit exclusively based on H→ZZ • expected 95 % CL excluded region is 135 GeV < MH < 188 GeV • H→bb and H→tt channels will help to improve sensitivity in low mass region [ATL-PHYS-PUB-2010-009] Higgs, SUSY and non-SUSY BSM in ATLAS

  31. Conclusion and Outlook • LHC and ATLAS collecting data at √s=7 TeV • remarkable performance of the detector • currently recorded data set: ~1.8 pb-1 • important for background and detector studies • already now sensitivity in some BSM models • e.g. excited quarks: mq* >1260 GeV • BSM sensitivity will improve rapidly ! • ~100 pb-1 by Nov 2010 • SUSY exclusion beyond Tevatron expected: ~10pb-1 • 1fb-1 by end of 2011 • e.g. discover Z’ up to 1.6 TeV; W’ up to 2.1 TeV • e.g. discover squarks and gluinos up to ~700 GeV • SM Higgs exclusion for 135 GeV<mH<188 GeV • The long awaited time of BSM/SUSY/Higgs data analysis at the LHC has just started ! Higgs, SUSY and non-SUSY BSM in ATLAS

  32. Search for heavy charged gauge bosons (W’) • prospects for the √s=7 TeV data period: • new sensitivity study available [ATL-PHYS-PUB-2010-007] • event selection: • one isolated lepton with pT> 50 GeV and |η|<2.5 • missing transverse energy: ET,miss > 50 GeV • specific cuts to suppress ttbar and dijet bgr • expected signal and background exp. cross sections after selection: electron channel muon channel MT[TeV] MT[TeV] Higgs, SUSY and non-SUSY BSM in ATLAS

  33. Search for heavy charged gauge bosons (W’) • prospects with √s=7 TeV data • luminosity needed for … … an exclusion at 95% CL: … a W’ discovery: [ATL-PHYS-PUB-2010-007] modified frequentist approach • 20 pb-1(fall 2010): ~1200 GeV • 100 pb-1(early 2011): ~1600 GeV • 1 fb-1 (end 2011): ~2300 GeV • for mW’=1 TeV already with ~10-20 pb-1 (fall this year) We are rapidly accessing unexplored regions Higgs, SUSY and non-SUSY BSM in ATLAS

  34. Search for heavy neutral gauge bosons (Z’) • current statistics too low What can we expect? • new sensitivity study performed for √s=7 TeV • event selection: • two isolated leptons with pT>20 GeV and |η|<2.5 • skip requirement of opposite charges at beginning • expected signal and background: • very clean signal: ~60 (6) fb for mZ’ = 1.0 (1.5) TeV • small background (%-level) from Drell-Yan and ttbar. exp. cross sections after sel.[fb]: [ATL-PHYS-PUB-2010-007] electron channel muon channel Higgs, SUSY and non-SUSY BSM in ATLAS

  35. SM Higgs: current situation • SM: Higgs needed for EWSB • EW precision data • (Gfitter) • exclusion from direct searches: • LEP : • Tevatron: ICHEP 2010 • prospects for Higgs evidence at Tevatron: • end 2011: >2.4 σ for all MH 3σ for MH=115 GeV • run III proposal: >3σ for MH< 185 GeV 4σ for MH =115 GeV 16 fb-1, run III proposal 10 fb-1, end of 2011 Higgs, SUSY and non-SUSY BSM in ATLAS

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