Searches for Strong Dynamics at the TEVATRON

Transcription

1 Searches for Strong Dynamics at the TEVATRON Hereafter I Present Preliminary Results on Behalf of the CDF and D0 Collaborations OUTLINE I. Introduction II. Search for Excited Electrons III. Search for Z in the Dilepton Channel IV. Search for Leptoquarks V. Conclusions and Prospects

2 I. Introduction The TEVATRON at Run II p 1.96 TeV Chicago p 2004 highlights Record lumi: 7.83x10 31 cm -2 s -1 Best D0 store: 2.19pb -1 First stores w/ antiprotons from Recycler (commissioning) CDF p DØ Booster p source Tevatron Main Injector & Recycler p High data taking efficiency in the range 80-90% So far analyzed around 200 pb -1 / expt

3 I. Introduction The TEVATRON at Run II D0 (23 May 04): Del d: 451 pb -1 Rec d: 356 pb -1 data for physics April 2001 Feb 2002 first data for analyses Jul 2002 detector commissioning

4 Muon System I. Introduction The CDF Detector at Run II Central Calorimeter Solenoid Silicon Microstrip Tracker Plug Calorimeter Time-of-Flight Drift Chamber Front End Electronics Pipelined Triggers / DAQ Online & Offline Software New Partly New Old

5 I. Introduction The D0 Detector at Run II

6 II. Search for Excited Electrons Production Mechanisms Contact Interaction Parameters: M e* compositeness scale Λ Gauge Mediation Parameters: M e* coupling f/λ (f relative coupling to Ζ) Search Channel and Topology Channel: e ± * e ± +γ Topology: 2e+γ

7 II. Search for Excited Electrons Signal Acceptance MC Generators: Pythia and CompHep Contact Interaction C: η e <1.1 EC: 1.2< η EM <2.8 Gauge Mediation

8 Low background analysis II. Search for Excited Electrons exp :3± 0.4 obs :3 SM Background Background Process γ+z 2γ+jets WZ MC Generator ZGAMMA PYTHIA PYTHIA All comb.

9 II. Search for Excited Electrons Integrated Background 3-body decays 2 body-decays

10 II. Search for Excited Electrons Data Candidate Run Evt p T (GeV) η det φ (rad) e ΕΜ ΕΜ ΕΜ 1 ΕΜ 2 e 1 e 1 ΕΜ 2 E/ T = 21GeV M(e 1 +ΕΜ 1 ) M(e 1 +ΕΜ 2 ) M(ΕΜ 1 +ΕΜ 2 ) M(e 1 +ΕΜ 1 +ΕΜ 2 ) 176 GeV 61 GeV 257 GeV 318 GeV

11 II. Search for Excited Electrons Exclusion Limits Contact Interaction M(e M(e ) > 889 GeV (obs) ) > 889 GeV (exp) * * For M e* =Λ,

12 II. Search for Excited Electrons Exclusion Limits Gauge Mediation For M e* = Λ, M(e M(e * * ) ) > > 208GeV (obs) 224 GeV (exp)

13 III. Search for Z in the Dilepton Channel Introduction Expected in models like: + Technicolor: ρ TC / ω TC, techni-meson mass M TC Z H + Little Higgs:, SU(2) Z H coupling parameter cotθ Sequential Z : ref. Model w/ SM-like couplings to leptons, sole parameter M Z Searches at the TEVATRON Run II CDF: acceptances and model for resonances as a function of new particle spin 0,1,2 search in high mass ee and µµ channels about 200 pb -1 analyzed for each channel Limit: from fitting dilepton mass spectra D0: acceptances and model of resonances determined for each specific model search in high mass ee channel about 200 pb -1 analyzed Limit: using mass window cuts and counting experiment

14 III. Search for Z in the Dilepton Channel Select 2 high p T isolated electrons (at least 1 track match) Overall efficiencies: ε CC 0.74± 0.02, ε = 0.74± 0.02 Main backgrounds at high mass: γ*/z (MC) QCD fakes (data) EC D0 Dielectron Channel = EC EC Total CC- CC 8246 CC- EC 5949 QCD fakes Signal acceptance: Pythia 6.2 and CTEQ5L Fast parametrized simulation for detector response 600 GeV Z

15 III. Search for Z in the Dilepton Channel D0 Dielectron Channel Systematic uncertainties: Several cancellations in the Z to Z cross section ratio Integrated lumi: 6.5% Signal syst. Uncert. K-factor E T, η depend. Accpet. Total 10% 7% 5% 13% Bkgd syst. QCD D-Y Uncert. 10% 10% Results: Obs: 0 Exp: 1.9

16 III. Search for Z in the Dilepton Channel Highest mass candidate: D0 Dielectron Channel E/ 8.8 T Type e + /e - E T E T η η φ φ M 475 cosθ 0.01

17 III. Search for Z in the Dilepton Channel Most stringent limit to date M Z >780 GeV (95% CL)

18 III. Search for Z in the Dilepton Channel 2e in CC-CC, CC-EC, EC-EC: p T > 25 GeV at least 1 track match CC: η e <1.1 EC: 1.2< η ΕΜ <2.8 CDF Dielectron Channel Accept. Spin 1

19 III. Search for Z in the Dilepton Channel Results: CC-CC: Obs: 0 Exp: 1.4 EC-EC: Obs: 0 Exp: 0.10+/-0.03 CDF Dielectron Channel 2 Tracks!!

20 III. Search for Z in the Dilepton Channel CDF Dielectron Channel

21 III. Search for Z in the Dilepton Channel CDF Dielectron Channel

22 III. Search for Z in the Dilepton Channel Muons CC-CC, CC-EC: p T > 20 GeV Isolated 1st: η <1 2nd: η <1.5 CDF Dimuon Channel Accept. Spin 1

23 III. Search for Z in the Dilepton Channel CDF Dimuon Channel Results: Obs: 0 ; Exp: 1.03

24 III. Search for Z in the Dilepton Channel CDF Dilepton Combined Limit

25 Production: qq/gg - >LQ+LQ (dominant) about 30% increase wrt Run I Decay: λ unknown coupling to l/ν and q β=br(lq->lq) Channels: LQ->lqor νq β 2 2β(1 β) (1 β) 2 IV. Search for Leptoquarks Introduction Scalar LQ: σ only depends on M LQ Vector LQ: σ also depends on 2 anom. couplings

26 IV. Search for Leptoquarks CDF 2j+E T Channel Event Selection: 2 or 3 jets: E T (j 1 ) > 40 GeV; E T (j 2 ) > 25 GeV ; E T (j 3 ) > 7 GeV E T > 55 GeV η 1,2 <1.0; η 3 <2.5 no other jets w/ E T > 7 GeV 100 o < φ(e T, j 1,2 ) < 165 o 80 o < φ(j 1, j 2 ) < 165 o 100 o < MIN φ(e T, j 2,3 ) < 165 o reject events w/ leptons 0.1 < EMF(j) < 0.9 at least 4 tracks in jet E/ T

27 Results: Obs: 124 Exp: /-14.5 IV. Search for Leptoquarks CDF 2j+E T Channel

28 IV. Search for Leptoquarks CDF 2j+2e Channel Event Selection: 2 CC electrons w/ E T > 25 GeV at least 1 track match reject events w/ 76 < M ee < 110 GeV E T (j 1 )+ E T (j 2 ) > 85 GeV E T (e 1 )+ E T (e 2 ) > 85 GeV sqrt([e T (j 1 )+ E T (j 2 )] 2 + [E T (e 1 )+ E T (e 2 ) ] 2 ) > 200 GeV Background: ttbar in 2e channel: 0.25+/ (Pythia) γ*/z+2j: 3.13+/- 2.8 (Alpgen+PS) Exp: 3.39+/-3.15 Obs: 0

29 Event Selection: 1 CC electron w/ E T > 25 GeV E T > 30 GeV; E T /sqrt(h T ) > 4.5 M T (E T, e) > 120 GeV E T (j 2 ) > 30 GeV E T (j 1 )+ E T (j 2 ) > 80 GeV φ(e T, j) > 10 o reject 2e events 1 track match Background: ttbar in 2e channel: 0.13+/ (Pythia) ttbar in l+jets channel: / (Pythia) W+2j: 1.60+/ (Alpgen+PS) Exp: 1.73+/-1.47 Obs: 2 IV. Search for Leptoquarks CDF 2j+e+E T Channel

30 IV. Search for Leptoquarks CDF LQ 1 Combined Limit

31 IV. Search for Leptoquarks CDF 2j+2µ Channel Background: γ*/z+2j, top and fakes Event Selection: 2µ (1 tight, 1 loose) p T (µ 1,µ 2 ) > 25 GeV Veto M µµ < 15 GeV Veto 75 < M µµ < 105 GeV p T (j 1 ) > 30 GeV; p T (j 2 ) > 15 GeV p T (j 1 ) + p T (j 2 ) > 80 GeV p T (µ 1 ) + p T (µ 2 ) > 80 GeV sqrt([p T (j 1 )+p T (j 2 )]²+ [p T (µ 1 )+p T (µ 2 )]²) > 200 GeV

32 IV. Search for Leptoquarks Results: Obs: 2 Exp: 3.17+/-1.17 CDF 2j+2µ Channel

33 IV. Search for Leptoquarks Event Selection: EM: p T > 25 GeV N EM >1; CC-CC or CC-EC at least 1 track match veto 80 < M ee < 102 GeV Global: H T > 450 GeV D0 2e+2j Channel Jets: N j >1 p T > 25 GeV η j <2.4 L dt = 175 ± 11pb Background: QCD fakes (data) γ*/z+jets (Alpgen+PS) ttbar in dielectrons (Pythia) 1

34 IV. Search for Leptoquarks D0 2e+2j Channel M ee =497 GeV H T =397 GeV (*) p T (EM)=130; 129; 22 GeV p T (jets)=71; 28 GeV ΕΜ 2 ΕΜ 3 j 1 j 2 ΕΜ 1

35 IV. Search for Leptoquarks Results: Obs: 0 Exp: 0.4+/-0.1 D0 2e+2j Channel

36 L dt = 175 ± 11pb IV. Search for Leptoquarks 1 D0 e+e T +2j Channel Event Selection: Background: EM: Jets: QCD fakes (data) N EM >0 N j >1 W+jets (Alpgen+PS) p T > 35 GeV p T > 25 GeV ttbar in e+jets (Pythia) CC or EC η j <2.5 1 isolated track match Global: E T > 30 GeV; φ(ν, e)>0.7; M T (e,ν)>130 GeV; H T >330 GeV

37 IV. Search for Leptoquarks Results: Obs: 2 Exp: 4.7+/-0.8+/-0.3 D0 e+e T +2j Channel M LQ >194 GeV

38 IV. Search for Leptoquarks D0 LQ1 Combined Limit

39 VI. Conclusions Search for Excited Electrons Me*=Λ (95% CL) Observed Limit Expected Limit Contact Interaction Gauge Mediation LEP (ADLO): 1.15/fb f/λ=0.1 Me*>200 GeV

40 VI. Conclusions Search for Z in Dileptons Expt Channel CDF ee CDF µµ CDF ee D0 ee D0 µµ... L dt (pb 1 ) Model 200 Little Higgs 200 Little Higgs 200 SM-like 200 SM-like (122) SM-like Observed Limit (GeV) (719)

41 Expt Channel CDF LQ 1 pairs->e T +2j CDF LQ 1 pairs-> 2e+2j / e+e T +2j / E T +2j CDF LQ 2 pairs-> 2µ+2j D0 LQ 1 pairs-> 2e+2j / e+e T +2j VI. Conclusions Search for Leptoquarks BR Observed L 1 dt (pb ) Limit (GeV) 191 not in [78,117] 72 β=0.1 β=0.5 β= (220) (3*) 198 β= β= (110) 175 β= (204) β= (225) (3*) Run I

42 VI. Prospects The TEVATRON Integrated Luminosity (pb -1 ) FY04 (as of June 3 rd, 2004): Delivered pb -1 Design goal pb -1 needed 9.6 pb -1 /week Base goal pb -1 needed 2.9 pb -1 /week FY04 FY03 FY02 FY04 Design FY04 Base Days Since October 1

43 BACK UP

44 I. Introduction The TEVATRON at Run II

45 II. Search for Excited Electrons SM Background In case the new signal undergoes 3-body decay

46 III. Search for Z in the Dilepton Channel CDF Dielectron Channel

47 IV. Search for Leptoquarks CDF 2j+E T Channel Signal region: E T > 60 GeV 80 o < φ(j 1,j 2 ) < 165 o No lepton (electron, muon) candidate (N l = 0) Control regions:

48 IV. Search for Leptoquarks Introduction