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:.3366; x.xxxx. Saturday, June 4,

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

3 Exotic 4th Generation Quarks S. Su Saturday, June 4,

4 Exotic 4th Generation Quarks chiral under SM gauge group S. Su Saturday, June 4,

5 Exotic 4th Generation Quarks charge under hidden symmetry chiral under SM gauge group S. Su Saturday, June 4,

6 Outline Motivation: general / specific Constraints Simulations and cut analysis Exclusion and discovery reach Conclusion S. Su 4 Saturday, June 4,

7 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 5 Saturday, June 4,

8 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 5 Saturday, June 4,

9 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 5 Saturday, June 4,

10 Dark matter motivation: WIMPless model WIMPless model (discrete symmetry) V = λ Q Lq L + B Rb R + T Rt R J.L. Feng and J. Kumar, PRL, 33 (8) Q L : T R : B R : 3,, 6 3,, 3 3,, 3. S. Su 6 Saturday, June 4,

11 Dark matter motivation: WIMPless model WIMPless model (discrete symmetry) V = λ Q Lq L + B Rb R + T Rt R J.L. Feng and J. Kumar, PRL, 33 (8) not chirality opposite chirality of SM quark Q L : T R : B R : 3,, 6 3,, 3 3,, 3. S. Su 6 Saturday, June 4,

12 Dark matter motivation: WIMPless model WIMPless model (discrete symmetry) V = λ Q Lq L + B Rb R + T Rt R J.L. Feng and J. Kumar, PRL, 33 (8) not chirality opposite chirality of SM quark Q L : T R : B R : 3,, 6 3,, 3 3,, 3. Exotic 4thgeneration mirror quarks S. Su 6 Saturday, June 4,

13 Dark matter motivation: WIMPless model WIMPless model (discrete symmetry) V = λ Q Lq L + B Rb R + T Rt R J.L. Feng and J. Kumar, PRL, 33 (8) not chirality opposite chirality of SM quark Q L : T R : B R : 3,, 6 3,, 3 3,, 3. Exotic 4thgeneration mirror quarks m g m g F 6π Ω M σv m g S. Su 4 6 Saturday, June 4,

14 Dark matter motivation: WIMPless model WIMPless model (discrete symmetry) V = λ Q Lq L + B Rb R + T Rt R J.L. Feng and J. Kumar, PRL, 33 (8) not chirality opposite chirality of SM quark Q L : T R : B R : 3,, 6 3,, 3 3,, 3. Exotic 4thgeneration mirror quarks indirect detection ff, YY direct detection f f m g m g F 6π Ω M σv m g S. Su 4 6 collider: 4th generation fermions Saturday, June 4,

15 3rd generation vs. the first two third generation loop level scattering, λ.3, more natural less constrained by FCNC first two generations, tree level scattering λ.3 Q q q Q g q g q q M. A. Shifman, A. I. Vainshtein and V. I. Zakharov, Phys. Lett. B 78, 443 (978). S. Su 7 Saturday, June 4,

16 Collider Signature: exotic quarks Y particle appears as exotic 4th generation mirror quarks Q DM p Qʼ p Qʼ q DM q Collider Signal T T tt, B B bb differ from SUSY searches: cascade decay differ from usual 4th generation quark T Wb, B Wt S. Su 8 Saturday, June 4,

17 Collider Signature: exotic quarks Collider Signal: T T tt, B B bb Connection to solution for Hierarchy problem need top partner the lighter, the more natural decay straight to invisible particles bottom partner appears in a general set of new physics scenarios asymmetric dark matter little Higgs with Tparity baryon and lepton number as gauge symmetry... B. Dutta and J. Kumar, ariv:.34 H.C. Cheng and I. Low, JHEP 48, 6 (4) P. Fileviez Perez and M. B. Wise, ariv:.754 S. Su 9 Saturday, June 4,

18 Constraints perturbativity constraints: mq = yq v, mq 6 GeV (if through Yukawa) precision electroweak data: mt mb 5 GeV (for SU() doublet) direct searches limits B B bb, similar to sbottom pair production with b b χ (pb) "! B D, L=5. fb (a) D LQ NLO cross section, B%BF(LQ $b# )= LQ NLO cross section, B=.5!F Leptoquark Mass 3 Observed limits Expected limits sp Bottom Squark Mass S. Su V. M. Abazov et al. [D Collaboration], 5. Neutralino Mass D, L=5. fb (b) m b Observed Expected = m b + m & ' LEP s=8 GeV D Run I 9 pb CDF Run I 88 pb D Run II 5. fb CDF Run II 95 pb D Run II 3 pb msb>47 GeV (95% C.L.) Saturday, June 4,

19 Constraints perturbativity constraints: mq = yq v, mq 6 GeV (if through Yukawa) precision electroweak data: mt mb 5 GeV (for SU() doublet) direct searches limits B B bb, similar to sbottom pair production with b b χ (pb) "! B D, L=5. fb (a) D LQ NLO cross section, B%BF(LQ $b# )= LQ NLO cross section, B=.5!F Leptoquark Mass 3 Observed limits Expected limits msb > 47 GeV sp Bottom Squark Mass S. Su V. M. Abazov et al. [D Collaboration], 5. Neutralino Mass 8 CDF mb 6 > 365 (44) GeV 4 D, L=5. fb (b) m b Observed Expected = m b + m & ' LEP s=8 GeV D Run I 9 pb CDF Run I 88 pb D Run II 5. fb Run II 95 pb D Run II 3 pb msb>47 GeV (95% C.L.) Saturday, June 4,

20 Constraints: direct search CDF, Run II,.5 fb, gluino pair production, g b b b b χ two or more jets, large MET, btagging T. Aaltonen et al. [CDF Collaboration], PRL, 8 (9). Cross Section [pb] CDF Run II (.5 fb ) pp g g at 95% CL limit (m[b ]=5 GeV/c ) Expected limit 95% CL limit (m[b ]=3 GeV/c ) Expected limit g s=.96 GeV b b bb (% BR) PROSPINO NLO (CTEQ6M) µ = µ = m( g) R F m( q)=5 GeV/c m( )=6 GeV/c (% BR) m( g) [GeV/c ] S. Su ] Sbottom Mass [GeV/c 35 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 (% BR) b b (% BR) m( ) = 6 GeV/c m( q) = 5 GeV/c D Run II 3 pb Sbottom Pair Production Excluded Region Gluino Mass [GeV/c ] Saturday, June 4,

21 Constraints: direct search CDF, Run II,.5 fb, gluino pair production, g b b b b χ two or more jets, large MET, btagging T. Aaltonen et al. [CDF Collaboration], PRL, 8 (9). Cross Section [pb] CDF Run II (.5 fb ) S. Su ] Sbottom Mass [GeV/c 35 CDF Run II (.5 fb ) g bb (% BR) mgluino > 34 GeV 5 m( for Δm GeV mb > 37 GeV pp g g at 95% CL limit (m[b ]=5 GeV/c ) Expected limit 95% CL limit (m[b ]=3 GeV/c ) Expected limit s=.96 GeV b b PROSPINO NLO (CTEQ6M) µ = µ = m( g) R F m( q)=5 GeV/c m( )=6 GeV/c (% 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 (% BR) b b (% BR) ) = 6 GeV/c Gluino Mass [GeV/c ] q) = 5 GeV/c D Run II 3 pb Sbottom Pair Production Excluded Region Saturday, June 4,

22 Constraints: direct search ATLAS, 35 pb, gluino+sbottom pair production lepton, 3 j (b) mgluino > 59 GeV [GeV] b m g g + b b production, g # b +b, ATLAS $ b # b+! " L dt = 35 pb, bjet channel, lepton, 3 jets m(! " ) = 6 GeV, m( q CDF b b.65 fb D 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 7 [GeV] g S. Su ATLAS Collaboration: Saturday, June 4,

23 Constraints: direct search ATLAS, 35 pb, gluino+sbottom pair production lepton, 3 j (b) mgluino > 59 GeV [GeV] b m g g + b b production, g # b +b, ATLAS $ b # b+! " L dt = 35 pb, bjet channel, lepton, 3 jets m(! " ) = 6 GeV, m( q CDF b b.65 fb, ) >> m(g ) s = 7 TeV g # b +b forbidden Reference point obs. limit 95% C.L. exp. limit 95% C.L. limits translated D b b 5. fb to B B bb is weak CDF g g, g # b +b.5 fb m 7 [GeV] g S. Su ATLAS Collaboration: Saturday, June 4,

24 Constraints: direct search CDF, Run II,.7 fb, stop pair production, t b χ ± b χ lν mst > 5 85 GeV, weaker than sbottom limit ) GeV/c M(! " CDF Run II Preliminary (.7 fb 85 ± M(! " )=5.8 GeV/c ± ± 8 BR( t! " BR (! " #! " $l)=. # b)= ± BR (! " #! " $l)=.5 #! " (! " ± BR $l)=.5 Observed 95% CL ) ) GeV/c M(! " ± CDF Run II Preliminary (.7 fb ) BR (! " #! " $l)=. 85 ± M(! " )=5.8 GeV/c ± 8 BR( t! " # b)= #! " (! " ± BR $l)=.5 Observed 95% CL #! " (! " ± BR $l)= Excluded by LEP M( t ) GeV/c 5 Excluded by LEP M( t ) GeV/c A. G. Ivanov [CDF Collaboration], ariv:8.788 [hepex]. S. Su 3 Saturday, June 4,

25 Constraints: direct search ATLAS, 35 pb, ttbar+met, lepton, >=4 j, + MET Events per GeV ATLAS Preliminary N jet!4, E miss T >8 GeV Data (35 pb QCD ) tt (SingleLepton) tt (Dilepton) Single Top Z + jets W + jets Diboson TT 75, 5 [GeV] TT 3, [GeV] Events per GeV 9 ATLAS Preliminary N jet!4, m > GeV T Data (35 pb ) 8 QCD tt (SingleLepton) tt (Dilepton) Single Top Z + jets W + jets Diboson TT 75, 5 [GeV] TT 3, [GeV] m T [GeV] miss E T [GeV] (a) m T (b) E miss T ATLASCONF36 S. Su 4 Saturday, June 4,

26 Constraints: direct search ATLAS, 35 pb, ttbar+met, lepton, >=4 j, + MET Events per GeV ATLAS Preliminary N jet!4, E miss T >8 GeV Data (35 pb QCD ) tt (SingleLepton) tt (Dilepton) Single Top Z + jets W + jets Diboson TT 75, 5 [GeV] TT 3, [GeV] Events per GeV 9 ATLAS Preliminary N jet!4, m > GeV T Data (35 pb ) 8 QCD tt (SingleLepton) tt (Dilepton) Single Top Z + jets W + jets Diboson TT 75, 5 [GeV] TT 3, [GeV] m T [GeV] miss E T [GeV] (a) m T mt > 75 GeV for m<5 GeV mt > 3 GeV for m< GeV (b) E miss T S. Su 4 ATLASCONF36 Saturday, June 4,

27 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 95, 7 (9) hadronic mode, spin and mass determination P. Meade and M. Reece, Phys. Rev. D 74, 5 (6). S. Su 5 Saturday, June 4,

28 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 95, 7 (9) hadronic mode, spin and mass determination P. Meade and M. Reece, Phys. Rev. D 74, 5 (6). S. Su 5 Saturday, June 4,

29 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 95, 7 (9) hadronic mode, spin and mass determination P. Meade and M. Reece, Phys. Rev. D 74, 5 (6). S. Su 5 Saturday, June 4,

30 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 =3,,m =4,,m =5, W+jets tt (e/µ) tt ( ) tt (e/µ) Cross section / bin (pb) LHC,m =3,,m =4,,m =5, W+jets tt (e/µ) tt ( ) tt (e/µ) Missing E T S. Su W M T Saturday, June 4,

31 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 =3,,m =4,,m =5, W+jets tt (e/µ) tt ( ) tt (e/µ) Cross section / bin (pb) SM bg peak around mw LHC,m =3,,m =4,,m =5, W+jets tt (e/µ) tt ( ) tt (e/µ) Missing E T S. Su W M T Saturday, June 4,

32 Semileptonic channel: precuts Njet 4 Cross section / bin (pb) 3 LHC,m =3,,m =4,,m =5, W+jets tt (e/µ) tt ( ) tt (e/µ) N(jets) Cross section / bin (pb) second, hadronically decay W LHC,m =3,,m =4,,m =5, W+jets tt (e/µ) tt ( ) tt (e/µ) S. Su 7 m jj Saturday, June 4,

33 Semileptonic channel: Tevatron Additional cuts: MET, mt W, HT he partonlevel generation. Tevatron: semileptonic Cut T (3) T (4) T (5) t t W +jets No cut (579) µ/e, noτ (6) /E T > GeV (78.8) m W T > GeV (36.6) 4jets m jj m W < GeV All precuts m W T > 5 GeV /E T > 5 GeV H T > 3 GeV /E T > 5, H T > fb S. Su 8 Saturday, June 4,

34 Semileptonic channel: LHC Additional cuts: MET, mt W, HT Cut LHC: semileptonic T (3) T (4) T (5) t t ( e/µ) t t ( τ) t t ( e/µ) W +jets No cut (4.8) µ/e, noτ (5.74) /E T > GeV (.33) m W T > GeV (.35) 4jets m jj m W < GeV All precuts Additional m W T cut: mw T > 5, GeV Additional E T cuts: E T > 5,, 5 GeV. H T = 4 i= pj T i + p l T cuts: H T > 4, 5 GeV. Combinations of the cuts above. 8 fb S. Su 9 Saturday, June 4,

35 Tevatron exclusion optimal cuts (after precuts) S/B >., more than events Poisson statistics m Exclusion for T T! t t at the Tevatron fb fb 5 fb = m + m t fb Semileptonic channel m Exclusion for T T! t t at the Tevatron fb = m + m t fb fb 5 fb Hadronic channel % C.L. 95% C.L. S. Su Saturday, June 4,

36 Tevatron exclusion optimal cuts (after precuts) S/B >., more than events Poisson statistics soft decay products m Exclusion for T T! t t at the Tevatron fb fb 5 fb = m + m t fb Semileptonic channel m Exclusion for T T! t t at the Tevatron fb = m + m t fb fb 5 fb Hadronic channel % C.L. 95% C.L. S. Su Saturday, June 4,

37 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 Saturday, June 4, 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.

38 LHC exclusion m Exclusion for T T! t t 5 5 mt = m + m t at TeV LHC Semileptonic channel 3 pb pb m Exclusion for T T! t t 5 5 mt = m + m t at TeV LHC Hadronic channel pb 3 pb pb pb % C.L. 95% C.L S. Su Saturday, June 4,

39 LHC exclusion offshell top m Exclusion for T T! t t 5 5 mt = m + m t at TeV LHC Semileptonic channel 3 pb pb m Exclusion for T T! t t 5 5 mt = m + m t at TeV LHC Hadronic channel pb 3 pb pb pb % C.L. 95% C.L S. Su Saturday, June 4,

40 Tevatron discovery m Discovery of T T! t t at the Tevatron 8 6 Semileptonic channel = m + m t m Discovery of T T! t t at the Tevatron 8 6 Hadronic channel = m + m t fb fb fb fb 5 fb fb fb 3 σ 3 σ S. Su 3 Saturday, June 4,

41 LHC discovery m Discovery for T T! t t at TeV LHC Semileptonic channel = m + m t m Discovery for T T! t t = m + m t at TeV LHC Hadronic channel 3 pb 3 pb pb 8 pb 8 pb 6 4 pb multiply lumonisity by a factor of 3. S. Su 4 3 σ 3 σ Saturday, June 4,

42 Tevatron search Signal: B B bb Bg: W(lν)jj, Z(νν) jj,wz, ttbar, single top. Precuts no lepton or 3 jets, with ηj <.5, PTj > GeV αjj < 64 o MET 4 GeV, MET/GeV > 8 4Δϕmin (MET, jets) bjets, including leading jet Δϕ(MET, jets) >.6, A=(METMHT)/(MET+MHT),. < A <. jj = (PTj+PTj)/HT, jj >.75 HT > 6 GeV Additional cuts PTj, MET, jj, HT S. Su 5 Saturday, June 4,

43 Tevatron reach Preliminary results for B B bb m Exclusion for B B! b b at Tevatron m B = m + m b fb fb 5 fb m B S. Su 6 m optimal cuts (after precuts) S/B >., more than events Poisson statistics Discovery for B B! b b at Tevatron m B 95% C.L. 3 σ Saturday, June 4, PRELIMiNARY = m + m b fb 5 fb fb m B PRELIMiNARY

44 Tevatron cross section reach Cross section limits for pp b b at Tevatron Cross section (pb) (B B ) PRELIMiNARY 5 discovery limit 3 discovery limit 95% exclusion limit L=5 fb L= fb S. Su Saturday, June 4, m B

45 LHC7 search Signal: B B bb Bg: W(lν)jj, Z(νν) jj,wz, ttbar, single top. Precuts no lepton or 3 jets, with ηj <.5, PTj >, 4 (4) GeV MET 8 GeV f=met/meff, f>.3 for jets, f>.5 for 3 jets Δϕ(MET, jets) >. Sphericity ST>. bjets, including leading jet Additional cuts PTj, MET, Meff, additional btag S. Su 8 Saturday, June 4,

46 LHC reach Preliminary results for B B bb optimal cuts (after precuts) S/B >., more than events Poisson statistics m Exclusion for B B! b b at 7 TeV LHC m B = m + m b 95% C.L. pb m B pb pb S. Su 9 Saturday, June 4, PRELIMiNARY m Discovery for B B! b b at 7 TeV LHC m B = m + m b 3 σ pb pb pb PRELIMiNARY m B

47 LHC7 cross section reach Cross section limits for pp b b at 7 TeV LHC Cross section (pb) (B B ) PRELIMiNARY 5 discovery limit 3 discovery limit 95% exclusion limit L= pb L= fb S. Su Saturday, June 4, m B

48 Conclusions Pair production of exotic quarks DM + SM particles DM motivated, e.g., WIMPless scenario T T tt semileptonic mode and hadronic mode Current CDF exclusion (4.8 fb ): 36 GeV Exclusion: TeV, 3 pb Discovery: m<3 GeV, mt < 45 GeV for Tevatron fb m<7 GeV, mt < 49 GeV for LHC 3 pb B B bb current exclusion (5. fb, D): 44 GeV Tevatron fb, exclusion, 47 GeV 7 TeV, fb, discovery: 545 GeV S. Su 3 Saturday, June 4,

49 Conclusions identify signal as T, B production,comparing with SUSY complementary between collider studies and DM searches small λ, DM searches unsuccessful displaced vertex at collider S. Su 3 Saturday, June 4,