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Experimental Searches for SUSY at the Tevatron

Experimental Searches for SUSY at the Tevatron. Monica D’Onofrio IFAE-Barcelona On behalf of the CDF and DØ collaborations SUSY’09 , Boston, USA, June 5-10, 2009. _. The Tevatron. Fermilab. p. p. Highest-energy accelerator currently operational  performing very well!. CDF. DØ.

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Experimental Searches for SUSY at the Tevatron

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  1. Experimental Searches for SUSY at the Tevatron Monica D’Onofrio IFAE-Barcelona On behalf of the CDF and DØ collaborations SUSY’09 , Boston, USA, June 5-10, 2009

  2. _ The Tevatron Fermilab p p Highest-energy accelerator currently operational  performing very well! CDF DØ Proton-antiproton: √s = 1.96 TeV Typical (peak) initial inst. Luminosity ~ 3.3 (3.5)*1032 cm-2 s-1 Integrated Luminosity/week(month)  ~ 75 pb-1/(260 pb-1) Integrated luminosity per year Peak luminosity Delivered: 6.8 fb-1 year: ‘02 ‘03 ‘04 ‘05 ‘06 ‘07 ‘08 ‘09 Experimental Searches for SUSY at the Tevatron, 6/5/09

  3. CDF and DØin RunII DØ CDF Took > 1 year of collisions to get to stable high efficiency (80-90%) Experimental Searches for SUSY at the Tevatron, 6/5/09

  4. Supersymmetry in 30’’ • The Standard Model is theoretically incomplete • Require fine tuning, account only for 4% of energy in Universe …. • SUSY: New spin-based symmetry relating fermions and bosons: •  Naturally solves the hierarchy problem Q|Boson> = Fermion Q|Fermion> = Boson gaugino/higgsino mixing • Define R-parity = (-1)3(B-L)+2s • R = 1 for SM particles • R = -1 for MSSM partners If conserved, provides Dark Matter Candidate (Lightest Supersymmetric Particle) • No SUSY particles found yet • SUSY must be broken  > 100 parameters even in “minimal” models Experimental Searches for SUSY at the Tevatron, 6/5/09

  5. Searching for SUSY The breaking mechanism determines thephenomenology and the search strategies • Model-inspired searches: • Explore large regions of parameter space • Theory driven: constrained MSSM models used as benchmark •  mSUGRA, GMSB, etc. • Signature-based searches: • Search for unusual final states with specialized analysis • Optimize selection to reduce backgrounds • Interpret the results in several models (GMSB, AMSB, RPV-SUSY etc.) • Global searches: • Maximize parameter space coverage • Less sensitivity but could give hint of deviation from SM predictions Experimental Searches for SUSY at the Tevatron, 6/5/09

  6. Outline SUPER • “Standard SUSY” searches • mSUGRA-inspired: • chargino/neutralino • Squarks and gluinos • GMSB-inspired: • Chargino/neutralino • “Non-Standard SUSY” searches • Bsmm • RPV SUSY (sneutrinos) • Long-Lived Particles • SUSY Hidden Valleys • Not only SUSY .. • Summary and Conclusions CDF: http://www-cdf.fnal.gov/physics/exotic/exotic.html DØ: http://www-d0.fnal.gov/Run2Physics/np/ Experimental Searches for SUSY at the Tevatron, 6/5/09

  7. Standard SUSY searches: mSUGRA • mSUGRA provides a good reference model (5 parameters) • Consider production with highest cross sections • Small masses (chargino/neutralinos) or large couplings (squark/gluino)  Squarks and gluinosheavy  1st and 2nd generation squarks are mass degenerate (pb) mixing of 3rd generation leads to light stop, sbottom and staumass m (GeV) Light gauginos alsoexpected • Final states depend on sparticle mass hierarchy and mixing (low/high tanb) Experimental Searches for SUSY at the Tevatron, 6/5/09

  8. ~ ~ c02c±1 production: “trileptons” ~ • Assume RP conservation, c01 is LSP • Low cross sections (σ x Br< 0.5 pb) • Very clean signature: • Missing ET due to undetected n, c01 • 3 isolated leptons ~ • 3 identified leptons (e,m) • 2 identified leptons + track (l) • “Tight” and “loose” e,m categories • 2 identified leptons + track (l) • mt+ l and mt+t(t had decay) • “low-pT” and “high-PT” searches 3.2 fb-1 2.3 fb-1 • Main backgrounds: • WW, WZ • Drell-Yan, W+jets, ttbar  Rejection using kinematic selections on: Ml+l-, N jets, Missing ET, Df between leptons... Experimental Searches for SUSY at the Tevatron, 6/5/09

  9. ~ ~ c02c±1 in trileptons: results Good agreement between data and SM prediction  set limit m0 = 60 GeV, tan b=3, A0=0, m>0 New! arXiv:0901.0646 (sub.to PLB, 2009) CDF @ 2 fb-1 ~ CDF excludes mc±1< 164 (155 Exp.) GeV/c2 Update@3.2 fb-1 results in PRL 101, 251801 (2008) in the same scenario (with 2.3 fb-1) DØ excludes mc±1< ~155(160 Exp.) GeV/c2 Study dependency on other parameters - exclude 1± of 130 GeV/c2 up to tan β =9.6 ~ ~ Experimental Searches for SUSY at the Tevatron, 6/5/09

  10. ~ ~ c02c±1 in trileptons: results Use common benchmark scenario: tan(β)=3, A0=0, μ>0 excluded region in mSUGRA m0-m½ space New! ~ ~ • Key-points: • Lepton coverage in h-f, t-selection • Luminosity: • ~10-20 GeV/c2 gained per 1 fb-1 • Limits depend on relative c02-lmasses • m2 > ml increases BR to e/ • m2 ≈ ml reduces acceptance • to lowest-pTlepton ~ ~ ~ ~ Experimental Searches for SUSY at the Tevatron, 6/5/09

  11. ~ ~ New! Heavy c02c±1 production • Assume: m(20,1±) > m(10)+m(W,Z) • Final state: e+e- pairs (Z), at least 2 jets (W) • and Missing ET (> 40, 50, 60 GeV) • Main Background: Z+jets ~ ~ ~ 86 < Me+e-< 97 GeV/c2 60 < Mdijet < 95 GeV/c2 W, Z bosons on shell L=2.7 fb-1 Missing ET > 40 GeV: Data: 7, SM Expected: 6.41 ± 0.95 M0 = 1000 GeV tan β= 10, m>0 M0 = 1000 GeV tan β= 10, m<0 observed cross sections ~ 1-3 pb Experimental Searches for SUSY at the Tevatron, 6/5/09

  12. Search for squarks and gluinos ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ PRL 102, 121801 (2009) PLB 660, 449 (2008) Similar results for CDF and DØ, probing sparticle masses ~ 400 GeV/c2 • Search for squark and gluino pair production in final states with 2, 3, or 4 jets and Missing ET • 2 jets + ET : qq → qq1010 (mq < mg) • 3 jets + ET : qg → qqq1010 (mq ~ mg) • 4 jets + ET : gg → qqqq1010 (mq > mg) Experimental Searches for SUSY at the Tevatron, 6/5/09

  13. Squarks in t, jets and Missing ET arXiv:0905.4086 Sub. to PLB • Assume large mixing scenario: • t1 is Next-LSP (“tau-corridor”) • m(g)>>m(q) qRqL dominates • Final states: • ≥ 2 Jets + Missing ET + ≥ 1 t (hadronic decay) • Perform 2 analysis (t-dijet, t-multijet), then combined • Optimization on Missing ET and ST = pj1T + pj2T + EtT ~ ~ ~ ~ ~ New! Observed: 2 events Exp.: 1.7  0.2 (stat.) +0.6-0.3(syst.) Further combined with inclusive squark/gluino analysis in 2/3 jets final states: Exclude m(q) < 410 GeV ~ Experimental Searches for SUSY at the Tevatron, 6/5/09

  14. ~ ~ g-mediated b production • Light sbottom in large mixing scenarios • Dedicated searches for b production • If m(b)<m(g) (assuming B.R. (bb c0) = 100%) • Search for b from gluino decays (sgg~ 10 sbb) ~ ~ ~ ~ ~ ~ ~ ~ ~ • Final state: Missing ET + 4 b-jets • Use b-tagging algorithm to identify at least 2 b-jets • 2 Neural Network to reject background (top and QCD-multijets) 2 optimization regions depending on g-b mass difference ~ ~ PRL 102, 221801 (2009) Experimental Searches for SUSY at the Tevatron, 6/5/09

  15. Stop searches Assumptions for stop searches at the Tevatron: • Rp conservation, mstop< mtop • (a) 2-body:if and • (b) 2-body: if allowed • (c) 3-body: (a) (b) (c) Lightest of the squarks Can be lighter than the top quark due to the large SM top mass 2-, 3-body decays possible Experimental Searches for SUSY at the Tevatron, 6/5/09

  16. Assume 100% B.R. Mass c01 in range [45-90] GeV Signature: 2 jets (at least one c-tagged) and Missing ET Stop searches: ~ PLB 665, 1 (2008) ~ ~ Stop masses excludedup to 150 GeV/c2if m(t)-m(c01)>60 GeV/c2 New results expected soon! Experimental Searches for SUSY at the Tevatron, 6/5/09

  17. Stop searches: • Assume on-shell charginos: • Signal topology depends on Dm = mt1 - mc • Signature: Missing ET+ 2 opposite-sign leptons + 2 b-jets (0 or ≥ 1 tag) •  Main background: top production (dilepton) • Reconstruct stop mass with a kinematic fit. ~ ~ New! Limits for several dilepton BR for 115 < m(t1)<197 GeV, 44 <m(c01)< 91 GeV. Fix to m(c±1) =105.8 and 125.8 GeV Experimental Searches for SUSY at the Tevatron, 6/5/09

  18. Stop searches: ~ • Assume sneutrino is LSP • Signal topology depends on Dm = mt1 - mn • Signature: Missing ET+ 2 opposite-sign leptons + 2 b-jets • CDF (1 fb-1): ee, em, mm ,DØ (1 fb-1): ee, em ~ ~ ~ ee+em+mm PLB 675, 289 (2009) New! For large Dm: mt1 < 175 GeV (DØ) mt1 < 180 GeV (CDF) ~ ~ Experimental Searches for SUSY at the Tevatron, 6/5/09

  19. ~ ~ GMSB: c02c±1 in gg+ Missing ET • SUSY breaking at scale L (10 -100 TeV) • Squarks, gluinos and sleptons heavy • Gravitino very light (<< MeV) and LSP • Neutralino or slepton can be NLSP • If NLSP is neutralino New! In Rp conservation scenario: 2 NLSP  2g + MET (+X) final states • Assume c01 (NLSP) short-lived • Optimize the gg+MET analysis for 0 ns lifetime •  Significant Missing ET and Large HT • HT = S (EM objects) + ETjets + Missing ET • Very low SM background • Zgg nngg, Wgg lngg Experimental Searches for SUSY at the Tevatron, 6/5/09

  20. c02c±1 in gg+ Missing ET : results No excess observed New! Mass(c01)>149 GeV/c2 for t ≤ 2 ns (Expected: M(c01)>141 GeV/c2) Limits on neutralino mass VS lifetime Experimental Searches for SUSY at the Tevatron, 6/5/09

  21. “Non-Standard” SUSY Searches Experimental Searches for SUSY at the Tevatron, 6/5/09

  22. Indirect searches: Bs  mm SUSY enhance ~(tanb)6 SM: BR = 3.42 10-9 Sensitive to new physics: SUSY particles show up in loops (or direct decays if Rp violation) CDF (2 fb-1): Br(Bs→mm)<5.8×10-8 @ 95% CL DØ (2 fb-1): Br(Bs →mm)<9.3×10-8 @ 95%CL New! Expected Limits at 5 fb-1(DØ): Br(Bs →mm)<5.3×10-8 @ 95%CL Expected Limits at 3.7 fb-1(CDF): Br(Bs →mm)<3.3×10-8@ 95%CL Unofficial CDF/DØ comb.: Br(Bs →mm)<4.5×10-8 Experimental Searches for SUSY at the Tevatron, 6/5/09

  23. Search for scalar neutrinos Update of PRL 100, 241803 (2008) (1. fb-1) L=1 fb-1 ~ Mass(nt)=500 GeV/c2 σ x BR upper limits of 0.018 pb (eμ), 0.037 pb (eτ), 0.052 pb (μτ) for m(nt ) = 800 GeV (with λ'311 = 0.1, λ132=λ133= λ231=0.05) limits on the σ x BR and RPV couplings λ’311 × λ312 for different sneutrino masses. ~ • Assume RP violation: possible production of single SuperPartner • Search strategy: look at high-mass unlike flavored lepton pairs: em(DØ), em, eth, mth(CDF)  probe the lijk- Msneutrino parameter space Experimental Searches for SUSY at the Tevatron, 6/5/09

  24. Charged massive stable particles Long-lived charginos are expected in some AMSB models with a “wino-LSP” (small  – 10 mass difference) They would appear like slowly-moving muons  Make use of thetime of flight information PRL 102 , 161802 (2009 ) arXiv:0902.1266 acc. by PRL m > 206 GeV CDF:Interpretation for strongly interacting charged massive particles, such as stops with a small stop- mass difference m(stop) > 250 GeV m > 171 GeV DØ: interpretation for charged gauginos (higgsinos) Experimental Searches for SUSY at the Tevatron, 6/5/09

  25. Supersymmetric Hidden Valleys • Hidden valley (HV) models: weakly coupled sector • Motivated by recent results from PAMELA, ATIC, EGRET, FERMI-LAT, HESS… • Phenomenology of SUSY HV similar to GMSB • Cascade to visible LSP • LSP decays into hidden sector • Photon + dark LSP (X = darkino) • Dark photon(gD )+ X (Missing ET) • Dark photon (~GeV) decays into fermions • BR (c01g/gD X): free parameters Mass Messenger(s) ~ ~ SUSY TeV ~ Final State: Missing ET, g, a pair of spatially close leptons Optimize for m(gD) < 2.5 GeV Dark SUSY GeV SM Visible sector Hidden sector never been investigated! Experimental Searches for SUSY at the Tevatron, 6/5/09

  26. SUSY Hidden Valley: results m(gD) = 1.4 GeV New! ~ BR=0.5 arXiv:0905.1478 sub. to PRL • Main background: • Multijet events with real/misidentified photons • Wln with real/misidentified photons • Set limits on chargino mass as a function of the dark photon mass and BR(c01g/gD X): Experimental Searches for SUSY at the Tevatron, 6/5/09

  27. Not only SUSY … Search for high-mass narrow resonances in the diEM channel RS Graviton (m<767 GeV for k/mp=0.1) SM Z’ (m<944 GeV) Search for G*, Z’, W’ in DiBoson Resonances RS Graviton (m<944 GeV for k/mp=0.1) Search for 1st generation LQ in ejej Search for B’ Search for t’ m(LQ) < 292 GeV ..and global searches carried out looking for the unknown m(B’) < 325 GeV m(t’) < 311 GeV Many more models explored by CDF/DØ Extra-Dimensions, Lepto-quarks , New gauge bosons, 4th gen. b/t quarks, Compositness, Hidden Valleys … Experimental Searches for SUSY at the Tevatron, 6/5/09

  28. Tevatron BSM Searches @ SUSY09 Biscarat Searches for Squarks and Gluinos Using Data from D0 Bhatti Search for Supersymmetry signatures in events with jets or photons at CDF Besancon Search for Charginos and Neutralinos with the D0 detector Strologas Search for trilepton SUSY signal at CDF Ivanov Searches in Dilepton Final States at CDF Ferapontov Searches for Extra Dimensions and for Heavy Resonances in Leptons, Photons, and MET Final States at D0 Goncharov Searches for extra dimensions at CDF Yoo Search for Anomalous Top Quark Production at D0 Moed Top Quark Production (including single top) at CDF Jabeen Search for New Physics Contamination in the Top Quark Samples at D0 Barfuss Searches for Leptoquark production in p p-bar collisions at the D0 experiment Johnson Search for Neutral Long-lived Particles Decaying to b-bbar at D0 Xie Search for Charged Massive Long-Lived Particles Using Data from D0 Culbertson Rare and exotic processes at CDF Gold Searches for new massive vector bosons with CDF Kraus Model Independent Search for New Physics in Leptonic Final States at D0 Gershtein Search for Hidden Valleys with Photons at D0 Ruiz-Jimeno Recent results on Bs→μμ and other FCNC decays from the CDF experiment Mackin Search for the Lightest Scalar Top Quark at D0 Experimental Searches for SUSY at the Tevatron, 6/5/09

  29. Conclusions GMSB: 10 fb-1 Bsmm Stay tuned for more results from the Tevatron! • CDF and DØ have a wide and rich program of SUSY searches: • Continuously on-going updates of existing results using more sophisticated techniques and more data • Many more results expected for Summer’09 • Covering “standard” and unusual scenarios, as well as the “unconsidered” ones. • No evidence of new physics yet, but.. expect to collect and analyze up to 10 fb-1 of data in the next years  Very promising projections Experimental Searches for SUSY at the Tevatron, 6/5/09

  30. Back-up

  31. Model independent searches PRD 79, 011101 (2009) New! • Out of 180 distributions, 4 significant deviations: • m + 2 jets + MET (9.3s) • m + g + 1 jet + MET (6.6s) • mm + MET (4.4s) • mm + g (4.1s) • Difficult modeling: none of these excesses are • “sign” for new Physics(Trigger modeling, • Photon mis-identification rate modeling, MC simulation) • Search for significant deviation from the SM • CDF: Use both Vista (model-independent) and Sleuth (quasi model-independent) to search for new phenomena in 2 fb-1 • DØ: Similar Vista/Sleuth approach looking at lepton-based final states in 1 fb-1 : Experimental Searches for SUSY at the Tevatron, 6/5/09

  32. Global searches results No indication of physics beyond the Standard Model. 5 most discrepant final states: P = probability that SM background for an individual final state would have a fluctuation at any cut that would be more significant than what is seen in data DØ Sleuth Results (1 fb-1) Final state P ℓ+ℓ′- + MET 2.9 E-6 ℓ + MET 0.00082 ℓ+ℓ′- 0.0031 ℓ+τ-+ MET 0.006 ℓ+ τ+ 0.0066 Experimental Searches for SUSY at the Tevatron, 6/5/09

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