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Supersymmetry at D Ø

PASCOS 2003. Supersymmetry at D Ø. and other new phenomena searches in Run II TeVatron and D Ø upgrade Run II preliminary studies mSUGRA : squarks and gluinos jet + mET GMSB : diphotons RPV : trileptons / likesign dileptons Extra-dimensions. Auguste BESSON for the D0 collaboration.

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Supersymmetry at D Ø

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  1. PASCOS 2003 Supersymmetry at DØ and other new phenomena searches in Run II TeVatron and DØ upgrade Run II preliminary studies mSUGRA : squarks and gluinos jet + mET GMSB : diphotons RPV : trileptons / likesign dileptons Extra-dimensions Auguste BESSON for the D0 collaboration

  2. TeVatron upgrade p CDF DØ Booster Fermilab Tevatron • p-pbar collider • Run IIa : march 2001 • Energy: 1.8  1.96 TeV • Luminosity • new injector : main injector • # bunches : 6 x 6 → 36 x 36 • pbar production  • pbar recycling : Recycler (Run IIb) p p source Main Injector & Recycler Auguste Besson for D0 collab.

  3. TeVatron upgrade (2) Auguste Besson for D0 collab.

  4. Run IIa : current luminosity • Maximum Luminosity • = 3.6 x 1031 cm-2s-1 • Delivered luminosity • ~ 150 pb-1 • (9 december 2002) week ∫L.dt on tape ~ 50 pb-1(october 2002) ~ 75 pb-1(mid-december 2002) date Auguste Besson for D0 collab.

  5. The DØ collaboration ~ 650 physicists; 76 institutions; 18 countries Auguste Besson for D0 collab.

  6. DØ upgrade • Run I • Calorimeter LAr/U, compensate • Run II upgrade • tracking Silicon vertex Fiber tracker • solenoid 2 T magnetic field • Preshower • Muons detector • Electronics - Trigger system Auguste Besson for D0 collab.

  7. Auguste Besson for D0 collab.

  8. MSSM / mSUGRA production Cross-sections Run II preliminary study: squarks/gluinos

  9. ~ ~ b1 b 20  10 e+ e- ~ Susy production • Neutralinos/charginos • trilepton channel • dilepton channel • sleptons cross-section small. • squarks/gluinos • jet + mET • single  + jets + mET • stops and sbottom Auguste Besson for D0 collab.

  10. cross-section (mSUGRA) A0 = 0; m0 = 100; tan  = 5;  < 0 m1/2 is the crucial parameter m0= 100 tan  = 5  < 0 ±0 Cross-section (pb) ±± sleptons For m1/2> 100 GeV and m0> 100 GeV pair production of Charginos/Neutralinos dominates squarks 00 m1/2 (GeV) Auguste Besson for D0 collab.

  11. Cross-section (squarks) • squark productions depend ‘’only’’ on their mass tan  = 5;  < 0; A0 = 0 Cross-section Squark-squark + Squark-antisquark m1/2 (GeV) Cross-section (pb) squark mass(GeV) m0 (GeV) Squarks dominate Auguste Besson for D0 collab.

  12. squarks and gluinos PRL 83, 4937 (1999) tan  = 2;  < 0; A0 = 0 • Final State >=2 jets + mET Run I L ~ 6 pb-1 significant cuts: mET, pTjets scalar sum of ET acoplanarity no EWSB D0 Run II preliminary - MC.  Data D0 Run II preliminary mET 2 jets (jet1-jet2) Auguste Besson for D0 collab.

  13. GMSB framework Run II preliminary study: di-photons + mET

  14. GMSB Fermilab Run II workshop: Baer et al. hep-ph/0008070 Baer et al. hep-ph/9903333 • Minimal Model of Gauge Mediation (MGM) 6 parameters : effective visible sector SUSY breaking parameter Nnumber of messenger Mmmass scale of messengers tan ratio of v.e.v. of the 2 higgs doublets sign()sign of mixing parameter of higgsinos CGratio of the messenger sector SUSY breaking order parameter to the intrinsic SUSY breaking parameter • NLSP nature. either: 01, stau, slepton, squark, etc. • lifetime of NLSP • signature: +mET; ll+mET ; +mET, monojet Auguste Besson for D0 collab.

  15. di-photons + mET D0. PRL 80, 3, 442 (1998) • Neutralino NLSP • Final state:  + mET + X N = 1; Mm = 2  ;tan  =15;  > 0 • Background W,Wj,Zee,tt,WW,WZ,etc. • Cuts: pT > 20 GeV, track veto (Jet,mET)>0.5 M  80-102 GeV, vertex mET > 25 GeV Run I Run II preliminary: D0 Run II preliminary 8.71.2 pb-1 - MC. + Data Auguste Besson for D0 collab.

  16. R-Parity violated (RPV) consequences LSP decay Run II preliminary study: like sign dileptons trileptons

  17. R-parity • SUSY potential: • i,j,k = 1,2,3(family indices)  9 + 27 + 9 = 45 new Yukawa couplings. • Lepton ( and ’) or Baryon (’’) number not conserved •  define R-parity : discrete quantum number • B= Baryon #, L=Lepton #, S=spin • Rp= +1  SM particle • Rp= -1  SUSY particle With Rp = (-1)3B+2S+L Auguste Besson for D0 collab.

  18. (-1) (+1) (+1) (-1) (-1) (+1) (+1) (+1) _ q g q _ ~ ~ q q R-parity: consequences • R-p conserved: • LSP stable and candidate for dark matter • Susy particles pair produced • R-p violated: B or L not conserved • Lightest Susy Particle (LSP) decays either • - inside the detector (with or without a displaced vertex) • outside the detector • Susy signature can be very different • Less missing Et • More leptons ( or ’)and jets (’ or ’’) • Single Susy particle production is possible • via ’ or ’’ @ TeVatron • cross-section  (’ijk)2 Auguste Besson for D0 collab.

  19. RPV example: ’122couplings • ’122 L1Q2D2 • Via ’122 _ (+ cplx. conjugate) OR Auguste Besson for D0 collab.

  20. D0, Phys. Rev. Lett. 83, 4476 (99) Run IIa simulation Run I ’122 :like sign dileptons A0 = 0 ;  < 0 ; tan  = 2 • Final state 2 likesign e + 4 jets • Backgd: Drell-Yan, Zee, tt, e+efake, wrong sign assignment • pT el > 15 GeV m1/2 (GeV) m0 (GeV) D0 Run II preliminary jet multiplicity for dielectrons events L = 9.7  1.4 pb-1 D0 Run II preliminary - MC. + Data Auguste Besson for D0 collab.

  21.  coupling: trilepton channel • Dominant coupling 121, 122 or233 LSP  2 charged leptons + 1  • Backgd: Drell-Yan, tt, Z, misidentification of jets as electrons, cosmic  Final State :  eee,ee,e, + missing ET D0 Run II preliminary L = 5.2 0.8 pb-1 Auguste Besson for D0 collab.

  22. Large Extra Dimensions

  23.  Instrumental - Inst. + S.M. backgd + Data Large extra dimensions • Virtual graviton • Planck scale Ms • final state ee, ,  S.M. L = 9.9 pb-1 Data QCD E.D. signal Run I Limit: (95% C.L.) Ms(GRW) > 1.2 TeV Run II preliminary: Ms(GRW) > 0.92 TeV cos * diEM Mass (GeV) Auguste Besson for D0 collab.

  24. di-photon candidate D0 Run II preliminary Auguste Besson for D0 collab.

  25. Conclusion • D0 detector: upgrade is a success tremendous effort on calibration, comissioning, instrumental backgd, particle ID, etc. • first new phenomena analysis underway • many exciting channels • Luminosity large progress during the last months • now: ~ 50 pb-1 on tape • ~ 200 pb-1 in summer 2003 • First Run II limits in the coming months. (better than the Run I results) Stay tuned ! Auguste Besson for D0 collab.

  26. Back up

  27. SUSY framework • SUSY • - New symmetry between fermions and bosons • - Solves hierarchy problem • - allows convergence of coupling constants at GUT scale • - complete new spectrum of susy particles. • In most of the models • - SUSY particles are pair produced • - The lightest SUSY particle (LSP) is stable and escape from detector. Auguste Besson for D0 collab.

  28. 2,3 and 4 body decays of stop Auguste Besson for D0 collab.

  29. RPV Experimental constraints • Indirect limits via low energy processes • e-- universality - Neutrinoless double-beta decay - Charged current universality - Top decay - Atomic parity violation - etc. • 2 limits for m = 100 GeV (limits often linear in mass) • Stronger limits on products of coupling -proton decay : ’’11k . ’11k < 10-22 ~ Barger et al. Phys.Rev. D40 (89) Ledroit, Sajot GDR-S-008 (98) Allanach et al., PRD 60 (99) ~ dk e+ _ u p d d u u Auguste Besson for D0 collab.

  30. ~ ~ ~  1- 1o _ d Resonant production : dimuons channel _ ~ • Dominant coupling ’211  resonant prod via RPV • Decay of LSP via RPV • Backgd : tt, Z+2jets, WW+jets • Cuts : pT  20 GeV ; pTjets  20 GeV Scalar ET  50 GeV ; Rjets  0.5 1o ~ u u d L _ _ d  u d l - d W - Final State :  2  + 2 jets l + Auguste Besson for D0 collab.

  31. Dimuons in m0-m1/2 plane A0 = 0 ;  < 0 ; tan  = 2 preliminary 95% conf. level • Run I: L = 94  5 pb-1 Events observed = 5 Expected Background = 5.34  0.07 • Run II: • (Fast simulation) • ’211=0.05 A0 = 0 ;  < 0 ; tan  = 1.5 Déliot et al., EPJ C 19 (01) 155 Auguste Besson for D0 collab.

  32. e1 e2 e3 ET = 17.9 GeV pT = 0.52 GeV  = 0.43  = 5.42 Charge= +1 ET = 13.9 GeV pT = 10.9 GeV  = -1.94  = 2.80 Charge= +1 ET = 13.2 GeV pT = 15.1 GeV  = 1.06  = 5.72 Charge= -1 me1e2 = 55.7 me1e3 = 10.8 me2e3 = 63.5 me1e2e3 = 85.2GeV/c2MET =10.7 GeV eee candidate event D Run 2 Preliminary Trilepton eventsare classical SUSY signature Electron Electrons Auguste Besson for D0 collab.

  33. MET e 1 2 pT = 28.2 GeV  = -0.10  = 6.20 Charge = -1 pT = 9.82 GeV  = -1.48  = 2.88 Charge = 1 ET = 19.2 GeV  = 0.40  = 0.63 No track match m = 41.5 GeV/c2 MET =31.8 GeV emm candidate event D Run 2 Preliminary D0 Run II preliminary Muon system Electron Muon Muon Auguste Besson for D0 collab.

  34. ee candidate event D0 Run II preliminary Auguste Besson for D0 collab.

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