SUSY at Accelerators (other than the LHC)

Transcription

1 SUSY at Accelerators (other than the LHC) Beate Heinemann, University of Liverpool Introduction Final LEP Results First Tevatron Run 2 Results Summary and Outlook IDM 2004, Edinburgh, September 2004

2 Why do we like SUSY? Why do we like SUSY? o Theoretical motivations (e.g. solves the hierarchy problem (M Pl /m EW ), includes gravity, ) o Good agreement with EW precision data and gauge coupling unification even in the simplest models o Provides a natural Cold Dark Matter candidate 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 2

3 Why do we like SUSY? Why do we like SUSY? o Theoretical motivations (e.g. solves the hierarchy problem (M Pl /m EW ), includes gravity, ) o Good agreement with EW precision data and gauge coupling unification new top mass even in the simplest models o Provides a natural Cold Dark Matter candidate 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 3

4 Supersymmetric Models Supersymmetric Models Gauge-Mediated SUSY breaking: GMSB: e.g. mgmsb(6) MSSM (>100) Anomaly-Mediated SUSY breaking: AMSB Constrained MSSM (6) and msugra (5) Supersymmetry ( < ) R-Paritv violation Provide natural Dark Matter candidate Will focus on MSSM (msugra and GMSB): provide natural dark matter candidate have most experimental results 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 4

5 How to look for SUSY How to look for SUSY o LSP = lightest neutralino (or sneutrino or stau) o Typical search : NLSP LSP + (SM particles), LSP undetected : E t o Sensitivity: o LEP: m NLSP ~ s / GeV o Tevatron: GeV (depends on particle) o Example topologies: squarks, gluinos chargino+neutralino GMSB 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 5

6 LEP II: Geneva LEP II: Geneva o e+e- collider at CERN: Energies GeV (~140 pb -1 / exp at E cm 206 GeV) o 4 experiments: o ALEPH, DELPHI, L3, OPAL o particle identification e ±, µ ±, τ ±, γ, b, c o Trigger efficiency ~ 100 % for E vis > 5 GeV o Accelerator and Experiments exceeded expectations for performance 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 6

7 LEP: final msugra limits LEP: final msugra limits o Theoretically excluded o LEP1 EWK precision measurements o Chargino searches o Selectron and stau searches o Higgs Search: Zh o Heavy stable stau 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 7

8 LEP: summary of LSP limits LEP: summary of LSP limits o o Interplay of several searches: o Charginos: in a large part of the parameter space m χ ~ M 1 M 2 /2 ~ m χ± /2 o Sleptons: M i appear in their masses through the RGEs o Higgs boson: through stop quark masses in radiative corrections msugra: o M(χ 10 )>50-60 GeV o tanβ 4 o Constrained MSSM o M(χ 10 )>46-50 GeV o tanβ 2 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 8

9 Tevatron Run II Upgrade completed in 2001 Accelerator: Run I s(tev) Δt(ns) L(cm-2 s-1) x x1032 Run II 1.96 Experiments CDF and D0 About 500 pb-1 of good data on tape => expect 2 fb-1 (4-9 fb-1) by 2006(2009) Analysed about 200 pb-1 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 9

10 Tevatron Performance Tevatron Performance Ldt= 680 pb -1 Max. L=1.03x10 32 cm -2 s -1 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 10

11 Charginos and Neutralinos Charginos and Neutralinos msugra inspired Neutralino LSP 3 leptons + E t ~ GMSB inspired: Gravitino LSP m(g) ~O(keV) Here: Neutralino (NLSP)->Gγ E t ~ 2 photons + + X ~ 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 11

12 3 leptons + 3 leptons + E t Challenge: σxbr low (<0.5 pb) Backgrounds large Selection 2 l (l=e,µ) + isolated track or µ ± µ ± Significant E t Topological cuts selection eel eµl background 0.7± ±0.3 observed 1 0 µµl 1.8±0.4 1 µ ± µ ± 0.1± /09 - IDM 2004 Searches for SUSY - B. Heinemann 12

13 msugra: 3-lepton result msugra: 3-lepton result Combined result: σxbr< pb Theory comparison msugra: m(χ ± )>97 GeV tanβ=3, A 0 =0, µ>0 M(χ ± ) M(χ 0 2 ) 2M(χ0 1 ) Heavy squarks: m(χ ± )>111 GeV Reduce destructive interference Large m 0 : Sleptons heavy Very difficult Will extend sensitivity beyond LEP with just 25% more data: Two times more already on tape! 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 13

14 GMSB: γγ+e t GMSB: γγ+e t Assume χ 0 1 is NLSP: Decay to G+γ ~ ~ G light M~O(1 kev) Inspired by CDF eeγγ+e t event: now ruled out by LEP D0 (CDF) Inclusive search: 2 photons: E t > 20 (13) GeV E t > 40 (45) GeV Exp. Obs. M(χ + 1 ) D0 2.5±0.5 1 >192 GeV CDF 0.3±0.1 0 >168 GeV 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 14

15 BR(B s ->µµ): Indirect Search: B s ->µµ Indirect Search: B s ->µµ SM: 3.5 x 10-9 (G. Buchalla, A. Buras, Nucl. Phys. B398, 285) SUSY: tan 6 β (G. Kane et al., hepph/ ) Selection: 2 muons, displaced vertex Topological cuts 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 15

16 BR(B s ->µµ): Indirect Search: B s ->µµ Indirect Search: B s ->µµ SM: 3.5 x 10-9 (G. Buchalla, A. Buras, Nucl. Phys. B398, 285) SUSY: tan 6 β (G. Kane et al., hepph/ ) Selection: 2 muons, displaced vertex Topological cuts 1x10-7 D0 (prel.) CDF expected 3.7± ±0.3 observed 4 1 Trileptons: 2fb -1 BR@90% C.L. <3.8x10-7 <5.8X10-7 Combined CDF+D0: BR<2.6x /09 - IDM 2004 Searches for SUSY - B. Heinemann 16

17 Bs->µµ vs DM cross section Bs->µµ vs DM cross section Probe SUSY parameter space consistent with WMAP data: msugra: just touching (P. Ko, SUSY 04) D0+CDF Non-minimal models (Cerdano, Munoz): already constraining Bs->µµ in competition with direct DM detection experiments M 0 =300 GeV, A 0 =0 D0+CDF 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 17

18 Bs->µµ vs DM cross section Bs->µµ vs DM cross section Probe SUSY parameter space consistent with WMAP data: msugra: not touched yet Non-minimal models (Cerdano, Munoz): already constraining Bs->µµ in competition with direct DM detection experiments Will achieve: <2x10-8 (P. Ko, SUSY 04) M 0 =300 GeV, A 0 =0 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 18

19 Summary and Outlook Summary and Outlook 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 19

20 Summary and Outlook Summary and Outlook LEP severely constrained msugra and beyond: LSP mass >50 GeV Chargino mass>103.5 GeV 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 20

21 Summary and Outlook Summary and Outlook Tevatron Run 2 has started and is running: 1st result available: direct and indirect Have started to constrain parameter space Expect times more data by start of LHC: 4-9 fb -1 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 21

22 Summary and Outlook Summary and Outlook LEP severely constrained msugra and beyond: LSP mass >50 GeV Chargino mass>103.5 GeV Tevatron Run 2 has started and is running: 1st result available: direct and indirect Have started to constrain parameter space Expect times more data by start of LHC: 4-9 fb -1 Hope we don t have to wait for the LHC to find Dark Matter at colliders! 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 22

23 Backup Slides Backup Slides

24 SUSY particles and parameters SUSY particles and parameters gravitino 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 24

25 The Higgs boson Precision measurements of M W = ± GeV/c 2 M top = GeV/c 2 Prediction of higgs boson mass within SM due to loop corrections Most likely value: 114 GeV Direct limit (LEP): m h >114.4 GeV Better prediction with expected improvements on W and top mass precision 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 25

26 Summary of CDF Higgs Searches Summary of CDF Higgs Searches 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 26

27 Higgs Discovery at Tevatron? Higgs Discovery at Tevatron? 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 27

28 Constraints on msugra Constraints on msugra allowed M. Drees Without DM constraints 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 28

29 Constraints on msugra Constraints on msugra allowed M. Drees With DM constraints 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 29

30 Squarks Typical signature: Jet and E t Interesting: Mixing of mass eigenstates 3rd generation squarks (stop, sbottom) could be very light (<200 GeV) Large production cross sections at Tevatron 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 30

31 Generic Squarks and Gluinos Generic Squarks and Gluinos Signature: 2 jets and P t jet > 275 GeV E t E t >175 GeV Observe: 4, Expect: 2.7±1.0 msugra ~ ~ Fix: m 0 =25 GeV, tanβ=3, A 0 =0,µ<0 Exclude: m(q/g) < 292/333 GeV Improves Run I limits: Include more data Scan parameter space QCD 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 31

32 High tanβ scenario: Sbottom could be light This analysis: Bottom Squarks Bottom Squarks Gluino rather light: GeV ~ ~ BR(g->bb)~100% assumed Spectacular signature: 4 b-quarks + E t Require b-jets and E t >80 GeV Expect:2.6±0.7 Observe: 4 Exclude new parameter space in gluino vs. sbottom mass plane 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 32

33 Sleptons and Charginos at LEP Sleptons and Charginos at LEP 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 33

34 Model: Stop Quarks Stop Quarks any charged massive particle (e.g. stop, stau) with long lifetime: quasistable Assume: fragments like b-quark Signature Use Time-Of-Flight Detector: R TOF 140cm Resolution: 100ps Heavy particle=> v<<c Δt TOF =t track -t event = 2-3 ns Result for Δt TOF >2.5 ns: expect 2.9±3.2, observe 7 σ<10-20pb at m=100 GeV ~ M(t)> %C.L. LEP: 95 GeV Δt TOF m(stop) 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 34

35 Luminosity Perspectives Luminosity Perspectives 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 35

36 CDF: COT Aging Problem Solved! CDF: COT Aging Problem Solved! 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 36

37 Silicon Performance Silicon Performance See talk by R. Wallny 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 37

38 CDF: B-tagging and tracking CDF: B-tagging and tracking See talk by R. Wallny 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 38

39 Model: RPV Neutralino Decay RPV Neutralino Decay R-parity conserving production => two neutralinos R-parity violating decay into leptons One RPV couplings non-0: λ 122, λ 121 Obs. Exp. Final state: 4 leptons +E t eee, eeµ, µµe, µµµ 3 rd lepton P t >3 GeV eel (l=e,µ) µµl (l=e,µ) ± Largest Background: bb Interpret: M 0 =250 GeV, tanβ=5 _ λ 122 >0 λ 121 >0 ~ ~ m(χ + 1) >160 GeV ~ m(χ + 1) >183 GeV 09/09 - IDM 2004 Searches for SUSY - B. Heinemann 39