Fourth Generation and Dark Matter

Transcription

1 Fourth Generation and Dark Matter Shufang Su U. of Arizona S. Su In collaboration with J. Alwall, J.L. Feng, J. Kumar ariv: ; 5.xxxx.

2 Not the usual 4th generation... t t q q S. Su

3 Tevatron Direct Search Crosssection [fb] Median 68% 95% Theory Observed Quark mass [GeV/c ] b tw t bw mbʼ > 37 GeV mtʼ > 358 GeV S. Su CDF Collaboration:.578

4 LHC Direct Search "(pp! b'b') [pb] > 36 GeV/c Limit at 95% CL: M b' NLO CMS 34pb expected observed s = 7 TeV s=7 TeV (Berger and Cao) Cross Section (pb) ATLAS Preliminary Ldt = 37.0 pb 95% CL NNLO from HATHOR Median Expected Limit Observed Limit ± σ ± σ CMS Collaboration:.4746 S. Su M b' [GeV/c b tw t, b qw mbʼ > 36 GeV ] Q 4 mtʼ, mbʼ > 70 GeV Mass (GeV/c ) ATLAS Collaboration: ATLASCONF0

5 b and t If m t > m b q t t q b S. Su Flacco, DW, BarShalom & Tait arvix: 05.77, PRL 0 Daniel Whiteson, LHC West Coast Irvine

6 Exotic 4th Generation Mirror Quarks S. Su

7 Exotic 4th Generation Mirror Quarks chiral under SM gauge group S. Su

8 Exotic 4th Generation Mirror Quarks chiral under SM gauge group same charge opposite chirality S. Su

9 Exotic 4th Generation Mirror Quarks chiral under SM gauge group charge under hidden symmetry same charge opposite chirality S. Su

10 Outline Motivation: general / specific WIMPless model Constraints Simulations and cut analysis Exclusion and discovery reach Conclusion S. Su 7

11 Dark matter motivation: general Dark Matter: longlived on cosmological time scale Charge under a new unbroken symmetry absolutely stable have only gravitational interaction with the SM can not be discovered at colliders couple to SM through connector Y YY production with y f Y f DM connector SM S. Su 8

12 Dark matter motivation: general Dark Matter: longlived on cosmological time scale Charge under a new unbroken symmetry absolutely stable have only gravitational interaction with the SM can not be discovered at colliders couple to SM through connector Y YY production with y f Y f DM connector SM SM charge & dark charge S. Su 8

13 Dark matter motivation: general Dark Matter: longlived on cosmological time scale Charge under a new unbroken symmetry absolutely stable have only gravitational interaction with the SM can not be discovered at colliders couple to SM through connector Y YY production with y f Y f DM connector SM SM charge & dark charge SUSY neutralino squark quark Rparity ExD KK gauge boson KK quark quark KKparity Our study DM(no SM charge) exotic quark quark dark charge S. Su 8

14 WIMP miracle WIMP m WIMP m weak g g weak Ω h 0.3 naturally around the observed value S. Su 9

15 WIMP miracle WIMP m WIMP m weak g g weak Ω h 0.3 naturally around the observed value S. Su 9

16 WIMPless miracle Ω σv m g 4 only fixes one combination of dark matter mass and coupling m/g ~ mweak/gweak, Ωh ~ 0.3 could have m mweak as long as the relation holds WIMPless DM J.L. Feng and J. Kumar, PRL, 330 (008) J.L. Feng, H. Tu and H. Yu, JCAP 08, 043 (008) J.L. Feng, M. Kaplinghat, H. Tu and H. Yu, JCAP 0907, 004 (009) dark matter: no SM gauge interactions, not WIMP naturally obtain right relic density: similar to WIMP S. Su

17 WIMPless model J.L. Feng and J. Kumar, PRL, 330 (008) Dark matter is hidden no SM interactions DM sector has its own particle content, mass m, coupling g Connected to SUSY breaking sector m g m g F 6π M Ω σv m g 4 right relic density! (irrespective of its mass) If no direct coupling to SM: interact only through gravity impact on structure formation no direct/indirect/collider signals S. Su

18 WIMPless: not hidden S. Su

19 WIMPless: not hidden my max (mweak, m) interaction λ Yf S. Su

20 WIMPless: not hidden my max (mweak, m) interaction λ Yf indirect detection ff, YY direct detection f f collider: 4th generation fermions S. Su

21 WIMPless: not hidden my max (mweak, m) interaction λ Yf indirect detection ff, YY direct detection f f open new possibility for DM model parameters new experimental search windows collider: 4th generation fermions S. Su

22 WIMPless: not hidden my max (mweak, m) interaction λ Yf indirect detection ff, YY direct detection f f light dark matter open new possibility for DM model parameters new experimental search windows collider: 4th generation fermions S. Su

23 Dark matter motivation: specific light DM with large SI not generic in typical WIMP SI : chirality flip, proportional to Yukawa coupling A. Bottino, F. Donato, N. Fornengo and S. Scopel, PRD 68, (003); PRD 77, 0500 (008); PRD 78, (008). can be easily accommodated in WIMPless model with connector Y J.L. Feng, J. Kumar and L.E. Strigari, PLB 670, 37 (008) S. Su 3

24 Explaining DAMA: WIMPless WIMPless model (discrete symmetry) V = λ Q Lq L + B Rb R + T Rt R Q L : T R : B R : 3,, 6 3,, 3 3,, 3. scattering: q Q q, q=b,t, induce coupling to gluon at loop M. A. Shifman, A. I. Vainshtein and V. I. Zakharov, Phys. Lett. B 78, 443 (978). Q q q g q S. Su 4 g

25 Explaining DAMA: WIMPless WIMPless model (discrete symmetry) V = λ Q Lq L + B Rb R + T Rt R not chirality opposite chirality of SM quark Q L : T R : B R : 3,, 6 3,, 3 3,, 3. scattering: q Q q, q=b,t, induce coupling to gluon at loop M. A. Shifman, A. I. Vainshtein and V. I. Zakharov, Phys. Lett. B 78, 443 (978). Q q q g q S. Su 4 g

26 Explaining DAMA: WIMPless WIMPless model (discrete symmetry) V = λ Q Lq L + B Rb R + T Rt R not chirality opposite chirality of SM quark Q L : T R : B R : 3,, 6 3,, 3 3,, 3. Exotic 4thgeneration mirror quarks scattering: q Q q, q=b,t, induce coupling to gluon at loop M. A. Shifman, A. I. Vainshtein and V. I. Zakharov, Phys. Lett. B 78, 443 (978). Q q q g q S. Su 4 g

27 Explaining DAMA: WIMPless WIMPless model m ~ GeV, mq ~ GeV, λ ~ 0.3, σsi in right range J.L. Feng, J. Kumar and L.E. Strigari, PLB 670, 37 (008) Q couples to b S. Su 5

28 3rd generation vs. the first two first two generations, tree level scattering λ ~ 0.03 Q q q third generation loop level scattering, λ ~ 0.3, more natural less constrained by FCNC S. Su 6

29 Collider Signature: exotic quarks Y particle appears as exotic 4th generation mirror quarks Q p Qʼ DM q DM Collider Signal T T tt, B B bb p Qʼ q differ from SUSY searches: cascade decay differ from usual 4th generation quark T Wb, B Wt appears in a general set of new physics scenarios asymmetric dark matter little Higgs with Tparity B. Dutta and J. Kumar, ariv:.34 baryon and lepton number as gauge symmetry... H.C. Cheng and I. Low, JHEP 0408, 06 (004) P. Fileviez Perez and M. B. Wise, ariv: S. Su 7

30 Constraints perturbativity constraints: mq = yq v, mq 600 GeV precision electroweak data: mt mb ~ 50 GeV direct searches limits B B bb, similar to sbottom pair production with b b χ 0 (pb) "! B D0, L=5. fb (a) D0 LQ NLO cross section, B%BF(LQ $b# )= LQ NLO cross section, B= 0.5!F Leptoquark Mass (GeV) 3 Observed limits Expected limits sp Bottom Squark Mass (GeV) S. Su 8 V. M. Abazov et al. [D0 Collaboration], 05. Neutralino Mass (GeV) D0, L=5. fb (b) m b ~ Observed Expected = m b + m & ' 0 LEP s=08 GeV D0 Run I 9 pb CDF Run I 88 pb D0 Run II 5. fb CDF Run II 95 pb D0 Run II 3 pb msb>47 GeV (95% C.L.)

31 Constraints perturbativity constraints: mq = yq v, mq 600 GeV precision electroweak data: mt mb ~ 50 GeV direct searches limits B B bb, similar to sbottom pair production with b b χ 0 (pb) "! B D0, L=5. fb (a) D0 LQ NLO cross section, B%BF(LQ $b# )= LQ NLO cross section, B= 0.5!F Leptoquark Mass (GeV) 3 Observed limits Expected limits msb > 47 GeV sp Bottom Squark Mass (GeV) S. Su 8 V. M. Abazov et al. [D0 Collaboration], 05. Neutralino Mass (GeV) CDF mb 60 > 365 (440) GeV 40 0 D0, L=5. fb (b) m b ~ Observed Expected = m b + m & ' 0 LEP s=08 GeV D0 Run I 9 pb CDF Run I 88 pb D0 Run II 5. fb Run II 95 pb D0 Run II 3 pb msb>47 GeV (95% C.L.)

32 Constraints B B bb, similar to sbottom pair production with b b χ CDF M~ b < M "! 0 + M b Observed Limit (95% C.L.) Expected Limit (95% C.L.) CDF D0 CDF (650 pb ) (3 pb ) (95 pb.... ).. ] [GeV/c M! " msb>30 GeV (95% C.L.) 0 o LEP # = S. Su 9 M~ T. Aaltonen et al. [CDF Collaboration], b [GeV/c ]

33 Constraints: direct search CDF, Run II,.5 fb, gluino pair production, g b b b b χ 0 two or more jets, large MET, btagging T. Aaltonen et al. [CDF Collaboration], PRL, 80 (009). Cross Section [pb] CDF Run II (.5 fb ) pp ~ g ~ g at 95% CL limit (m[b ~ ]=50 GeV/c ) Expected limit 95% CL limit (m[b ~ ]=300 GeV/c ) Expected limit ~ g ~ s=.96 GeV b b ~ bb (0% BR) PROSPINO NLO (CTEQ6M) µ = µ = m( ~ g) R F ~ 0 m( q)=500 GeV/c m( )=60 GeV/c (0% BR) m( ~ g) [GeV/c ] S. Su 0 ] Sbottom Mass [GeV/c 350 CDF Run II (.5 fb ) % CL limit Expected limit g ~ bb ~ kinematically forbidden CDF Run II 56 pb Excluded Region CDF Run I excluded ~ ~ g bb (0% BR) ~ 0 b b (0% BR) 0 m( ) = 60 GeV/c m( ~ q) = 500 GeV/c D0 Run II 3 pb Sbottom Pair Production Excluded Region Gluino Mass [GeV/c ]

34 Constraints: direct search CDF, Run II,.5 fb, gluino pair production, g b b b b χ 0 two or more jets, large MET, btagging T. Aaltonen et al. [CDF Collaboration], PRL, 80 (009). Cross Section [pb] CDF Run II (.5 fb ) S. Su 0 ] Sbottom Mass [GeV/c 350 CDF Run II (.5 fb ) ~ ~ g bb (0% BR) ~ mgluino > 340 GeV 50 m( ~ for 0 Δm ~ 0 GeV mb > 370 GeV pp ~ g ~ g at 95% CL limit (m[b ~ ]=50 GeV/c ) Expected limit 95% CL limit (m[b ~ ]=300 GeV/c ) Expected limit s=.96 GeV b b PROSPINO NLO (CTEQ6M) µ = µ = m( ~ g) R F ~ 0 m( q)=500 GeV/c m( )=60 GeV/c (0% BR) m( ~ g) [GeV/c ] % CL limit Expected limit g ~ bb ~ kinematically forbidden CDF Run II 56 pb Excluded Region m( CDF Run I excluded ~ ~ g bb (0% BR) ~ 0 b b (0% BR) ) = 60 GeV/c Gluino Mass [GeV/c ] 0 q) = 500 GeV/c D0 Run II 3 pb Sbottom Pair Production Excluded Region

35 Constraints: direct search ATLAS, 35 pb, gluino+sbottom pair production 0 lepton, 3 j (b) mgluino > 590 GeV [GeV] b ~ m ~ g g ~ + ~ b ~ ~ 0 b b # b+! " production, g ~ # b ~ +b, ATLAS $ L dt = 35 pb, bjet channel, 0lepton, 3 jets 0 m(! " ) = 60 GeV, m( q ~ ~ CDF b b ~.65 fb ~ ~ D0 b 5. fb b CDF g ~ ~ g, ~ g #, ) >> m(g ~ ) ~ b +b.5 fb s = 7 TeV ~ g # b ~ +b forbidden Reference point obs. limit 95% C.L. exp. limit 95% C.L m 700 [GeV] g ~ ATLAS Collaboration: S. Su

36 Constraints: direct search CDF, Run II,.7 fb, stop pair production, t b χ ± b χ0 lν mst > GeV, weaker than sbottom limit ) GeV/c 0 M(! " CDF Run II Preliminary (.7 fb 85 ± M(! " )=5.8 GeV/c ± 0 ~ ± 80 BR( t! " BR (! " #! " $l)=.0 # b)= ± 0 BR (! " #! " $l)=0.50 #! " 0 (! " ± BR $l)=0.5 Observed 95% CL ) ) GeV/c 0 M(! " ± 0 CDF Run II Preliminary (.7 fb ) BR (! " #! " $l)=.0 85 ± M(! " )=5.8 GeV/c ~ ± 80 BR( t! " # b)= #! " 0 (! " ± BR $l)=0.50 Observed 95% CL #! " 0 (! " ± BR $l)= Excluded by LEP ~ M( t ) GeV/c 50 Excluded by LEP ~ M( t ) GeV/c A. G. Ivanov [CDF Collaboration], ariv: [hepex]. S. Su

37 Constraints: direct search ATLAS, 35 pb, gluino+sbottom/stop pair production Cross section [pb] ~ ~ g ~ g + t lepton, j (b) mgluino > 50 GeV ~ t production, ~ g # bjet channel, lepton, jets 0 ± 0 m(! " ) = 60 GeV, m(! " ) % m(! " ) m( ~ q ) >> m( ~ g ), ~ ~ t t " +t, # b+! m~ = GeV t ± NLO Prospino obs. limit 95% C.L. exp. limit 95% C.L. $ ATLAS L dt = 35 pb, s = 7 TeV m~ = 80 GeV t ATLAS Collaboration: m~ [GeV] g S. Su 3 Figure 3: Observed and expected 95% C.L. upper limits, as obtained with the onelepton analysis, on the gluinomediated and stop pair

38 Simulation MadGraph Pythia PGS Signal: T T t ( ) t ( ) bw + bw hadronic channel: large cross section SM backgrounds, tt, W, have MET with lepton irreducible background: Z νν + jets semileptonic channel: isolated lepton, suppress QCD background purely leptonic channel: suppressed cross section Similar analyses in the literature semileptonic mode, high mass, large luminosity T. Han, R. Mahbubani, D. G. E. Walker and L. T. E. Wang, JHEP 0905, 7 (009) hadronic mode, spin and mass determination P. Meade and M. Reece, Phys. Rev. D 74, 050 (006). S. Su 4

39 Simulation MadGraph Pythia PGS Signal: T T t ( ) t ( ) bw + bw hadronic channel: large cross section SM backgrounds, tt, W, have MET with lepton irreducible background: Z νν + jets semileptonic channel: isolated lepton, suppress QCD background purely leptonic channel: suppressed cross section Similar analyses in the literature semileptonic mode, high mass, large luminosity T. Han, R. Mahbubani, D. G. E. Walker and L. T. E. Wang, JHEP 0905, 7 (009) hadronic mode, spin and mass determination P. Meade and M. Reece, Phys. Rev. D 74, 050 (006). S. Su 4

40 Simulation MadGraph Pythia PGS Signal: T T t ( ) t ( ) bw + bw hadronic channel: large cross section SM backgrounds, tt, W, have MET with lepton irreducible background: Z νν + jets semileptonic channel: isolated lepton, suppress QCD background purely leptonic channel: suppressed cross section Similar analyses in the literature semileptonic mode, high mass, large luminosity T. Han, R. Mahbubani, D. G. E. Walker and L. T. E. Wang, JHEP 0905, 7 (009) hadronic mode, spin and mass determination P. Meade and M. Reece, Phys. Rev. D 74, 050 (006). S. Su 4

41 Semileptonic channel: precuts Signal:T T tt bbjj l + MET Precuts one isolated electron or muon large MET large mt W m W T m T (p l T, p T ) = p l T p T cos( φ(p l T, p T )) Cross section / bin (pb) LHC,m =300,,m =400,,m =500, W+jets tt (e/µ) tt ( ) tt (e/µ) Cross section / bin (pb) LHC,m =300,,m =400,,m =500, W+jets tt (e/µ) tt ( ) tt (e/µ) Missing E (GeV) T S. Su W (GeV) M T

42 Semileptonic channel: precuts Signal:T T tt bbjj l + MET Precuts one isolated electron or muon large MET large mt W m W T m T (p l T, p T ) = p l T p T cos( φ(p l T, p T )) Cross section / bin (pb) LHC,m =300,,m =400,,m =500, W+jets tt (e/µ) tt ( ) tt (e/µ) Cross section / bin (pb) SM bg peak around mw LHC,m =300,,m =400,,m =500, W+jets tt (e/µ) tt ( ) tt (e/µ) Missing E (GeV) T S. Su W (GeV) M T

43 Semileptonic channel: precuts Njet 4 Cross section / bin (pb) 3 LHC,m =300,,m =400,,m =500, W+jets tt (e/µ) tt ( ) tt (e/µ) N(jets) Cross section / bin (pb) second, hadronically decay W LHC,m =300,,m =400,,m =500, W+jets tt (e/µ) tt ( ) tt (e/µ) (GeV) S. Su 6 m jj

44 Semileptonic channel: Tevatron Additional cuts: MET, mt W, HT he partonlevel generation. Tevatron: semileptonic Cut T (300) T (400) T (500) t t W +jets No cut (579) µ/e, noτ (060) /E T > 0 GeV (78.8) m W T > 0 GeV (36.6) 4jets m jj m W < GeV All precuts m W T > 50 GeV /E T > 50 GeV H T > 300 GeV /E T > 50, H T > fb S. Su 7

45 Semileptonic channel: LHC Additional cuts: MET, mt W, HT Cut LHC: semileptonic T (300) T (400) T (500) t t ( e/µ) t t ( τ) t t ( e/µ) W +jets No cut (4.8) µ/e, noτ (5.74) /E T > 0 GeV (.33) m W T > 0 GeV (0.35) 4jets m jj m W < GeV All precuts Additional m W T cut: mw T > 50, 00 GeV Additional E T cuts: E T > 50, 00, 50 GeV. H T = 4 i= pj T i + p l T cuts: H T > 400, 500 GeV. Combinations of the cuts above. 8 fb S. Su 8

46 Hadronic channel: precuts Signal: T T tt bbjjjj + MET Precuts Background: leptonic W decay with lepton missed tau lepton mistagged as jets Z νν + jets Cross section / bin (pb) Cross section / bin (pb) No isolated electron, muon, tautagged jets large MET LHC,m =300, m T,m =300, m T,m =400,,m =400, m T m,m T,m =500, =500, Z+jets Z+jets W+jets W+jets tt (hadronic) tt (hadronic) tt (e/µ) tt (e/µ) tt (!) tt (!) Cross section / bin (pb) Njet 5 LHC,m =300,,m =400,,m =500, Z+jets W+jets tt (e/µ) tt (!) S. Su Missing Missing E (GeV) E (GeV) T T N(jets),m =300, m T,m =300, m,m =400, m,m =400,

47 Hadronic channel: precuts φ(/p T,p j T ) o reduce the suppress QCD bg Cross section / bin (pb) 3 after Precuts LHC,m =300,,m =400,,m =500, Z+jets W+jets tt (e/µ) tt ( ) Cross section / bin (fb) after Precuts LHC,m =300,,m =400,,m =500, Z+jets W+jets tt (e/µ) tt ( ) Missing E (GeV) (after precuts) T S. Su (GeV) (after precuts) H T

48 Hadronic channel: precuts Cross section / bin (pb) 3 φ(/p T,p j T ) o reduce the after Precuts suppress QCD bg LHC,m =300,,m =400,,m =500, Z+jets W+jets tt (e/µ) tt ( ) Cross section / bin (fb) tau background: important for new physics with jets and MET. after Precuts LHC,m =300,,m =400,,m =500, Z+jets W+jets tt (e/µ) tt ( ) Missing E (GeV) (after precuts) T S. Su (GeV) (after precuts) H T

49 Hadronic channel: Tevatron Additional cuts: MET, HT, Njet n the partonlevel generation. Tevatron: hadronic Cut T (300) T (400) T (500) t t W +jets Z+jets No cut (579.06) ( ) 0isolatedleptons (756.96) (545.) /E T > 0 GeV (663.5) (9.) 5jets φ cuts All precuts fb Additional E T cuts: E T > 50, 00, 50 GeV. H T = 5 i= pj T i cuts: H T > 300, 350, 400 GeV. At least 6 jets with p j T > 0 GeV. Combinations of the cuts above. S. Su 3

50 Hadronic channel: LHC Additional cuts: MET, HT, Njet in pb. Cut LHC: hadronic T (300) T (400) T (500) t t ( τ) t t ( e/µ) t t (had) W +jets Z+jets No cut (4.8) (8.86) 0isolatedleptons (6.8) (5.7) /E T > 0 GeV (.5) (.48) 5jets φ cuts All precuts Additional E T cuts: E T > 50, 00, 50, 300 GeV. H T = 5 i= pj T i cuts: H T > 400, 500 GeV. At least 6 jets with p j T > 40 GeV. Combinations of the cuts above..4 pb S. Su 3

51 Tevatron exclusion optimal cuts (after precuts) S/B > 0., more than events Poisson statistics (GeV) m Exclusion for T T! t t at the Tevatron fb fb 5 fb = m + m t 0 fb Semileptonic channel (GeV) m Exclusion for T T! t t at the Tevatron fb = m + m t 0 fb fb 5 fb Hadronic channel % C.L. 95% C.L. S. Su (GeV) (GeV)

52 Tevatron exclusion optimal cuts (after precuts) S/B > 0., more than events Poisson statistics soft decay products (GeV) m Exclusion for T T! t t at the Tevatron fb fb 5 fb = m + m t 0 fb Semileptonic channel (GeV) m Exclusion for T T! t t at the Tevatron fb = m + m t 0 fb fb 5 fb Hadronic channel % C.L. 95% C.L. S. Su (GeV) (GeV)

53 Tevatron Searches (CDF) Search for Production of Heavy Particles Decaying to Top Quarks and Invisible Particles in p p collisions at s =.96 TeV ] [ GeV/c m T. Aaltonen et al. [CDF Collaboration], ariv: [ GeV/c S. Su 34 Expected exclusion Observed exclusion m t = m Semileptonic 4.8 fb 95% C.L. ] 3 Cross section upper limit [fb] [] J. [] J. [3] H [a [4] P. ph [5] M W [6] D 7 [7] A Le la [8] C ax pr p T [9] F.

54 LHC exclusion (GeV) m Exclusion for T T! t t mt = m + m t at TeV LHC Semileptonic channel 300 pb 00 pb (GeV) m Exclusion for T T! t t mt = m + m t at TeV LHC Hadronic channel 0 pb 300 pb 00 pb 0 0 pb % C.L. 95% C.L (GeV) (GeV) S. Su 35

55 LHC exclusion offshell top (GeV) m Exclusion for T T! t t mt = m + m t at TeV LHC Semileptonic channel 300 pb 00 pb (GeV) m Exclusion for T T! t t mt = m + m t at TeV LHC Hadronic channel 0 pb 300 pb 00 pb 0 0 pb % C.L. 95% C.L (GeV) (GeV) S. Su 35

56 Tevatron discovery (GeV) m Discovery of T T! t t at the Tevatron Semileptonic channel = m + m t (GeV) m Discovery of T T! t t at the Tevatron Hadronic channel = m + m t fb fb 0 fb fb 5 fb fb 0 fb 0 3 σ 0 3 σ (GeV) (GeV) S. Su 36

57 LHC discovery (GeV) m Discovery for T T! t t at TeV LHC Semileptonic channel = m + m t (GeV) m Discovery for T T! t t = m + m t at TeV LHC Hadronic channel 300 pb pb pb pb 80 0 pb pb (GeV) (GeV) multiply lumonisity by a factor of 3. S. Su σ 3 σ

58 Tevatron Search Signal: B B bb Bg: W(lν)jj, Z(νν) jj,wz, ttbar Precuts no lepton or 3 jets, with ηj <.5, PTj > 0 GeV αjj < 64 o MET 40 GeV, MET/GeV > 80 40Δϕmin (MET, jets) bjets, including leading jet Δϕ(MET, jets) > 0.6, A=(METMHT)/(MET+MHT), 0. < A < 0. jj = (PTj+PTj)/HT, jj > 0.75 HT > 60 GeV Additional cuts PTj, MET, jj, HT S. Su 38

59 Tevatron Reach Preliminery results for B B bb optimal cuts (after precuts) S/B > 0., more than events Poisson statistics m (GeV) fb PRELIMENARY fb mb (GeV) m (GeV) fb fb PRELIMENARY 0 fb 95% C.L. 3 σ 0 fb mb (GeV) S. Su 39

60 LHC7 Search Signal: B B bb Bg: W(lν)jj, Z(νν) jj,wz, ttbar Precuts no lepton or 3 jets, with ηj <.5, PTj > 0, 40 (40) GeV MET 80 GeV f=met/meff, f>0.3 for jets, f>0.5 for 3 jets Δϕ(MET, jets) > 0. Sphericity ST>0. bjets, including leading jet Additional cuts PTj, MET, Meff, additional btag S. Su 40

61 LHC Reach Preliminery results for B B bb optimal cuts (after precuts) S/B > 0., more than events Poisson statistics m (GeV) PRELIMENARY m (GeV) fb 0. fb 50 fb 50 fb 95% C.L. fb 3 σ fb mb (GeV) mb (GeV) PRELIMENARY S. Su 4

62 Conclusions Pair production of exotic quarks DM + SM particles DM motivated, WIMPless scenario natural obtain the right relic density explain DAMA results: light DM, large σsi T T t t semileptonic mode and hadronic mode Current CDF exclusion (4.8 fb ): 360 GeV Exclusion: TeV, 300 pb Discovery: m<30 GeV, mt < 405 GeV for Tevatron 0 fb m<70 GeV, mt < 490 GeV for LHC 300 pb S. Su 4

63 Conclusions B B bb current exclusion (5. fb, D0): 440 GeV Tevatron 0 fb, exclusion, 470 GeV 7 TeV, fb, discovery: 545 GeV identify signal as T T t t,comparing with SUSY complementary between collider studies and DM searches small λ, DM searches unsuccessful displaced vertex at collider t t t t χ 0 χ 0 S. Su 43