1 / 26

R-parity violation at DØ. Run I results and Run II prospects

PHENO 2002 SYMPOSIUM. R-parity violation at DØ. Run I results and Run II prospects. On behalf of the DØ collaboration Auguste Besson (ISN-Grenoble, France). R-parity violation at DØ. The TeVatron and the DØ detector R-parity violating SUSY (RPV) Pair production and RPV decays of LSP

stanislaus-duscha
Télécharger la présentation

R-parity violation at DØ. Run I results and Run II prospects

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. PHENO 2002 SYMPOSIUM R-parity violation at DØ.Run I results and Run II prospects On behalf of the DØ collaboration Auguste Besson (ISN-Grenoble, France) Auguste Besson

  2. R-parity violation at DØ • The TeVatron and the DØ detector • R-parity violating SUSY (RPV) • Pair production and RPV decays of LSP •  and ’ couplings • Resonant sparticle production • ’ and ’’ couplings • Top decay via RPV • ’ and ’’ couplings • Conclusion and outlook Auguste Besson

  3. Run 1b Run 2a Run 2b #bunches 6 x 6 36 x 36 140 x 103 s (TeV) 1.8 1.96 1.96 typ L (cm-2s-1) 1.6x1030 8.6x1031 5.2x1032  Ldt (fb-1) ~ 0.13 ~ 2 ~ 15 bunch xing (ns) 3500 396 132 interactions/xing 2.5 2.3 4.8 TeVatron DØ CDF MI. + Recycler The TeVatron • Run II started March 2001 • Increased Luminosity • Main injector, Recycler • # bunches, # antiprotons • Increased Energy • 1.8 to 1.96 TeV Auguste Besson

  4. Run IIa current Luminosity • typical Luminosity • ~ 1031 cm-2s-1 • Integrated L • ~ 36 pb-1 delivered Auguste Besson

  5. The DØ upgrade • Run I • excellent calorimetry LAr/U, hermetic, compensation • Run II upgrade • New tracking Silicon tracker Fiber tracker • Central solenoid 2 Teslas - Preshower - Forward muon system - Electronics - Triggers Auguste Besson

  6. Supersymmetry • 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

  7. 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 nb, L=nb Lepton nb, S=spin • Rp= +1  SM particle • Rp= -1  SUSY particle •  not excluded theoritically With Rp = (-1)3B+2S+L Auguste Besson

  8. R-parity violating : consequences • The Lightest Susy Particle (LSP) decays either • - inside the detector (with or without a displaced vertex) • outside the detector (similar to Rp conserved analysis) • Susy signature can be very different • Less missing Et • More leptons ( or ’) and jets (’ or ’’) • Single Susy particle production is possible • via ’ or ’’ @ TeVatron • LSP is not anymore a candidate for dark matter (-1) (+1) (+1) (+1) Auguste Besson

  9. 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

  10. RPV search at DØ : hypothesis • mSUGRA framework (m0 ; m1/2 ; A0 ; sign  ; tan ) • LSP • Only one Yukawa coupling (ijk,’ijk,’’ijk) dominates • Pair production  all pair production included, then 2 LSP decay via RPV. • If RPV coupling is large  resonant production is possible Auguste Besson

  11. Pair production: dielectron channel • 2 susy particles produced  2 LSP • Dominant coupling ’1jk (j=1,2 ; k=1,2,3) • If LSP decays inside the detector: coupling not to small,(’1jk >~ 10-3) LSP  1 e + 2 jets • Background: Drell-Yan, tt, Ze+e- + jets, misidentification of jets as electrons • Cuts: pTel  15 & 10 GeV; pTjet  15 GeV; Mee  76-106 GeV Final State : 2 electrons + 4 jets _ _ Auguste Besson

  12. Dielectron channel : m0-m1/2 plane A0 = 0 ;  < 0 ; tan  = 2 D0, Phys. Rev. Lett. 83, 4476 (99) • Run I results : L = 99 pb-1 , s = 1.8 TeV - Expected Backgd : 1.8  0.2  0.3 - Events observed : 2 • Run II : L = 2fb-1, s = 2 TeV • Scenario I Extrapolation from Run I • Scenario II upgraded detector ~ mg ~ 550 GeV mq ~ 500 GeV ~ Run II : Allanach et al. hep-ph/9906224 Auguste Besson

  13. Pair production: dimuon channel • Similar analysis • Dominant coupling ’2jk • Backgd : Drell-Yan, tt, Z+jets, Z,WW + jets • Cuts : pT > 15 & 10 GeV, pTjets > 15 GeV, Scalar ET > 150 GeV, M>5GeV, Acoplanarity > 0.03 • Run I : L = 77.5  4 pb-1 Events observed = 0 Expected Background = 0.18  0.03  0.02 Final State : 2 muons + 4 jets Auguste Besson

  14. dimuon channel : m0-m1/2 plane A0 = 0 ;  < 0 ; tan  = 2 Run II (2fb-1) Run I D0, hep-ex/0111053 Submitted to PRL. Auguste Besson

  15. Pair production: multileptons channel • Dominant coupling 121, 122 or233 LSP  2 charged leptons + 1  • Backgd: Drell-Yan, tt, Z, misidentification of jets as electrons • Run I : Final State :  eee,ee,e, + missing ET D0, PRL 80, 1592 (1998) D0, Phys. Rev. D Rapid. Comm.62, 071701 (2000) Auguste Besson

  16. multileptons channel : m0-m1/2 plane • Contours : • 121, 122 or233  < 0 or > 0 tan  = 5, 10 Auguste Besson

  17. 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

  18. 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 Muon system Electron Muon Muon Auguste Besson

  19. ~ ~ ~  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

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

  21. ~ ~ ~  1- 1o _ d Resonant production : 3 leptons channel u d Final State : 3  + 2 jets l - d W - l + Mass reconstruction Fast simulation: M̃01=77.7 GeV (MC input) 2 jets and softer muon: M̃01=71 GeV (9) Lint = 10fb-1 ’211 = 0.09 A0 = 0 ;  < 0 ; tan  = 1.5 Déliot et al., EPJ C 19 (01) 155 Auguste Besson

  22. ~ 1o ~ l 1+ ~ d t W l s b Resonant Squark Production • Dominant coupling ’’3jk  Resonant stop production  Stop decays to b  to which decays outside the detector • Backgd: W+b-fake,Wbb,Wcc, single top • Cuts: pTb > 40 GeV ; pTlepton > 20 GeV;no other lepton or jet • Run I: 110 pb-1 Final State : 1 charged lepton, 1 b-jet + missing ET Berger et al.,PRD 63, 115001 (01) Auguste Besson

  23. Resonant Squark Production • Run II studies : ’’3jk , 2 fb-1 • Perspectives with Fast simulation (SHW) Berger et al.,PRD 63, 115001 (01) Auguste Besson

  24. 5.00 2.00 1.00 0.50 0.20 0.10 0.05 ’’331 150 160 170 180 190 Sbottom Mass (GeV) Top decay via RPV : Run II studies _ • ’’331 dominant coupling • tt production  t bd  t W-b lb • decays outside the detector • Backgd : tt, Wbbj • Cuts : pT> 20 GeV, || < 2.5, Rjj > 0.5 • Run II studies (fast simulation, 2fb-1) + ’’333 studies _ _ _ Final state: 1 lepton + 2 b-jets + 1 jet + ETmiss _ Han et al. Phys. Lett.B 476 79 (2000) Abraham et al. Phys.Lett.B 514 72 (2001) Eilam et al. Phys.Lett.B510227 (2001) Auguste Besson

  25. Conclusion • RUN I : many channels and couplings explored • RUN IIa : • improved detector ; Lint10 ; 10% more energy • DØ is already taking data. ~ 300 pb-1 expected at the end of 2002. ~ 2 fb-1 in 2004. • Great discovery potential both in pair/single production. No RPV signal found Auguste Besson

  26. Feynman diagrams • Via ’122 Auguste Besson

More Related