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Supersymmetry @ Tevatron

Supersymmetry @ Tevatron. Peter Wittich University of Pennsylvania For the D Ø and CDF Collaborations April 19 APS 2005. Supersymmetry. Based on fundamental symmetries String theories are supersymmetric Solves some technical problems of Standard Model How: double particle spectrum!

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Supersymmetry @ Tevatron

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  1. Supersymmetry @ Tevatron Peter Wittich University of Pennsylvania For the DØ and CDF Collaborations April 19 APS 2005

  2. Supersymmetry • Based on fundamental symmetries • String theories are supersymmetric • Solves some technical problems of Standard Model • How: double particle spectrum! • Worked before: postulate positron for quantum electro dynamics • Introduce “super-partners” with different spin • Makes theory self-consistent • Also provides dark matter candidate • But: where are they? • m(positron)=m(electron) • But not so for selectron • SUSY is broken! • Should be visible in near future, at Tevatron collider or at next generation (LHC) Dark Matter Candidate Peter Wittich - U Penn

  3. Experimental SUSY signatures • Rp (R-parity) conserving • Lightest Supersymmetric Particle (LSP) is stable, escapes detector (undetected) • Results in large ETMiss • striking exp. Signature • (Rp violating signatures) • Often include lepton flavor violating decays Breaking Models: • mSugra: supergravity-inspired • Best-studied model, 5 parameters • GMSB-motivated signatures • LSP: Gravitino, various next-LSP (NLSP) • Experimentally: photons! • Run 1 CDF eggETMiss • AMSB-motivated signatures • Long-lived particles, soft pions • Very hard at hadron colliders Peter Wittich - U Penn

  4. Tevatron at Fermi National Accelerator Lab • Tevatron circulates protons (p’s) and anti-protons (pbar’s) • Particle beams collide at experiment sites (CDF, DØ) • Energy in C.O.M.: ~2 TeV • Now have >600/pb of data on tape • Current analyses 200-390/pb • Run 2 goal: 4.4-8.5/fb • Take data until 2009 • Tevatron is Energy Frontier until LHC turn-on Peter Wittich - U Penn

  5. Tevatron Experiments: DØ & CDF • Well-understood, mature detectors • Excellent particle ID, coverage, tracking and triggering =1.0 =0 =1.0 =2.0 =3.0 =3.8 Peter Wittich - U Penn

  6. Gauginos • Squarks & Gluinos • Rp violating decays • Other and indirect searches Peter Wittich - U Penn

  7. Chargino-Neutralino Searches • Recall: • @ Tev: Look for lightest chargino, 2nd neutralino • Final state with many leptons, large ETMiss from LSP • One of the SUSY “golden modes” • Small SM backgrounds but small (EW) cross sections • Striking signature “Charginos” “Neutralinos” Gaugino, Higgsino content, m(slepton) determines BR’s, coupling strengths Peter Wittich - U Penn

  8. Chargino and Neutralino in 3+ETMiss In models with Rp:3 leptons+ETMiss • sxBR~0.2 pb • Very clean signature • SM background very small 6 analyses: -2l(l=e,m,t)+isolated track or mm - ETMissand topological cuts (Mll,Df, MT) M(mm) (GeV/c2) Peter Wittich - U Penn

  9. Chargino Neutralino Limits “3l-max” Limits : • M(c±1)>116 GeV/c2 “Heavy Squarks” • M(c±1)>128 GeV/c2 “Large m0” • M(~)>>M(c02 ,c±) • No sensitivity due to smaller leptonic BR’s A0=0 adding t’s improves sensitivity (low tan b) Limit: sxBR ~ 0.2 pb Start testing above LEP limit for mSugra—but LEP Model Independent ! Peter Wittich - U Penn

  10. CDF is also in the game… Chargino-neutralino in eechannel SELECTION: -2 electrons+  ( =e,m ) | h | < 1 - largeETMiss>15 GeV/c2 - 15<Mll<76, >106 GeV/c2 - |Df|< 160 - Njets(20 GeV) <2 ETMiss>15 VERY FIRST LOOK AT THE DATA!! Still a lot to do: - improve acceptance: forward e’s - add the other channels Peter Wittich - U Penn

  11. CDF-I eeggET event ET (GeV) Chargino-Neutralino in gg+ETMiss In GMSB: 2 photons+ETMiss D0(CDF) Event selection: -2 photons ET > 20(13) GeV -ETMiss>40(45) GeV CDF and D0 combined result: m(c±)>209 GeV/c2 hep-ex/0504004 Peter Wittich - U Penn

  12. Gauginos • Squarks & Gluinos • Rp violating decays • Other and indirect searches Peter Wittich - U Penn

  13. Lightest squark: Squark-gluino searches • Large strong-interaction cross sections • Another “golden mode” at Tevatron • Typical searches, generic: search for jets + ETMiss • Use to suppress bkgnds • Signal-specific:3rd family can look quite different! • Large mixing • Stop: due to large mt. • Sbottom: due to large tanb. specific generic Target w/special searches Peter Wittich - U Penn

  14. ~ ~ ~ ~ ~ • Limits (tanb=3, A0=0,m<0, q=u,d,c,s,b): • 2j :M0=25 GeV -> M(q) > 318 GeV/c2 • 3j :M(g)=M(q) -> M(q) > 333 GeV/c2 • 4j :M0=500 GeV-> M(g)> 233 GeV/c2 ~ ~ ~ ~ ~ Squarks and Gluinos in jets+ETMiss L=310 pb-1 • In mSUGRA: Njets+ ETMiss selection • 3 analyses 4 jet Extended LEP mSUGRA reach for M(~q)<M(~g) Peter Wittich - U Penn

  15. Gluino-Squark in jets + ETMiss Require HT>350 New CDF result! • 254/pb of data • Trigger: 2 jets + ETMiss>35 • ≥3 jets (125, 75, 25 GeV) • ETMiss>165 GeV, HT>350 • Expect 4.2  1.1 bkgnd events (SUSY: 0.7-4.8) • Observe 3 events in data • Scan parameter space, set limit soon Require ETMiss>165 Peter Wittich - U Penn

  16. Light Stop in mSugra In mSugra with stop NLSP, assume selection:2 jets, large ETMiss, no l, charm tag Limit on sxBR Peter Wittich - U Penn

  17. Gauginos • Squarks & Gluinos • Rp violating decays • Other and indirect searches Peter Wittich - U Penn

  18. R-parity • Global symmetry of MSSM • All analyses presented so far assume Rp is conserved • Kills (B-L) violating terms of Lagrangian • No proton decay • no flavor-violating decays  • LSP is stable: good dark matter candidate  • What if RP is not conserved? • Global symmetries are theoretically shaky • Introduce new terms in MSSM • Can produce single sparticles • No stable LSP: no dark matter candidate, no ETMiss. • But no one says SUSY has to solve all our problems… Lepton-number violating terms Baryon-number violating terms Peter Wittich - U Penn

  19. - d - d ~  0 1 ~ ´211 + l133 ´211 l122 ~ u - m+ - m- - u RPV Sleptons • RPV tested in Production and Decay of SUSY particles m- • Resonant sparticle production • l’ijk coupling • Selection: 2jets+2 isolated m’s • l’211 • RPV decay of LSP(c01) • lijk coupling • Selection:3+ETMiss+channel-dependent cuts • l121 -> em. • l122 -> me • l133 -> te Peter Wittich - U Penn

  20. RPV Slepton limits • (L=154 pb-1) : l’211 • (L=160 pb-1) : l122 M(c0(+)1)>84(165) GeV/c2 • (L=238 pb-1) : l121M(c0(+)1)>95(181) GeV/c2 • (L=200 pb-1) : l133M(c0(+)1)>66(118) GeV/c2 Resonant production: Minimal Rp violation in decay only: Peter Wittich - U Penn

  21. Stop in RP–violating SUSY (I) • Assume • BR(t1bt) ~ 100% • Search for : ~ l’333 selection:1 (=e,m)+ 1t +  2 jets Biggest background: Real t from Ztt  Check in 0 jet bin control region Ztt visible Peter Wittich - U Penn

  22. Stop in RP–violating SUSY (II) • Control region looks good • Search in signal region • Limit: m(stop)>129 GeV/c2 Peter Wittich - U Penn

  23. Gauginos • Squarks & Gluinos • Rp violating decays • Other and indirect searches Peter Wittich - U Penn

  24. b m+ W+ nm t s m- W- b m+ H0 H+ t m- s BR(Bs) (I) Standard Model: • Indirect search for SUSY • Process greatly enhanced by SUSY • Complimentary to direct searches • Complimentary • Can restrict generic high tanb models • Challenging: • SM prediction is 3.4×10-9 • Use sidebands, same-sign data to understand backgrounds in Bs mass region SUSY enhancement prop to (tan b)6 Peter Wittich - U Penn

  25. BR(Bs) (II) New CDF result with many improvements • Use B+J/y K+ normal. Mode (lower B pT) • Include 0.6 < |h|<1.0 m’s, also in trigger • Multivariate discriminant for more rejection power • n(Expected BG) = 1.47 ± 0.18 for ±60 MeV/c2 and LH > 0.99 • n(Observed) = 0 2x improvement wrt prev. best published result Peter Wittich - U Penn

  26. L=390 pb-1 cut Charged massive stable particle search • Look for particle that is • charged • Massive: v<<c • Lifetime long enough to decay outside detector (ct>10 m) • Massively ionizing • (Not used) • Event Selection: • 2 muons pT> 15 GeV, isolated • Speed significantly slower than c ~ ~ Peter Wittich - U Penn

  27. Champs (II) • Estimate backgrounds from data • sv<0, Z boson data • SUSY interpretation: Set limits for (quasi)-stable staus, charginos • Stau: GMSB-like models • Charginos: AMSB-like models Limits: In GMSB: champ = t (NLSP) In AMSB: champ = c ±1 • M(c±1)>174 GeV/c2 ~ ~ Not sensitive yet Peter Wittich - U Penn

  28. http://www-cdf.fnal.gov/physics/exotic/exotic.html http://www-d0.fnal.gov/Run2Physics/WWW/results/np.html In Conclusion… • SUSY promising venues for new physics • DØ and CDF both mounting extensive program – this is just a small taste! • Gluino-squark • Chargino-neutralino • R-parity violating modes • Stop, sbottom, sneutrino, rare b decays, … • Starting to exclude new regions in parameter space • Stay tuned for more data, more channels, … Peter Wittich - U Penn

  29. Backup Slides Peter Wittich - U Penn

  30. Delivered Luminosity • Current record initial luminosity >12×1032/cm2/s • Frequent records before shutdown • Goal: 300/pb delivered in FY04 was reached • Run analyses currently using ~240/pb-390/pb • Run 2 goals: “Base:” 4.4 fb-1. “Design:” 8.5 fb-1 Peter Wittich - U Penn

  31. BR(Bsmumu) in SUSY • Dashed blue lines are are contours of constant BR( Bs → μμ ) • dashed black lines are are contours of constant higgs mass • green areas are regions of parameter space consistent with the observed relic density of dark matter • pink areas are excluded. Peter Wittich - U Penn

  32. CDF Acquired Luminosity Peter Wittich - U Penn CDF had 430/pb on tape at start of 2004 shut-down

  33. Lightest squark: SUSY searches with Rp conservation Look for classes of particles • Sleptons: … • Gaugino searches • “Chargino-Neutralino” • (small) EWK cross sections • Typically search via decays into leptons • Squark, gluino Searches • (large) strong-interaction cross sections • Typical searches, generic: search for jets + ETMiss • Signal-specific:3rd family can look quite different! • Large mixing • Stop: due to large mt. • Sbottom: due to large tanb. Target w/special searches Peter Wittich - U Penn

  34. Bs (I) Complementary to other SUSY searches, indirect BR could be enhanced from new physics: loop decays (MSSM, mSugra) or direct (RP viol.) Challenging: SM prediction is 3.4 x 10-9 ... Sidebands and same-sign data used to optimize cuts and check background estimates SM signal x 10 5 Use lifetime information to reduce backgrounds Peter Wittich - U Penn

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