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1 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London Beyond the Standard Model Searches at the Tevatron Gérard Sajot LPSC Grenoble On behalf of the CDF and D0 Collaborations
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2 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 2 OutlineOutline Recent CDF and D0 results from “RunIIa” 1.1 fb -1 (April 2002-February 2006) - Leptoquarks - Compositness lepton - 4 th generation of quarks - Extra Gauge Bosons W’ Z’ - Extra Dimensions Monojets, di-leptons and di-photons Not covered in this talk : - SUSY : talk by Volker Buescher (plenary July 4th) - Technicolor, Little Higgs - … See also CDF+D0 talk by Tommaso Dorigo (parallel session July 3rd)
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3 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 3 LeptoquarksLeptoquarks LQ : predicted by models Beyond Standard Model (GUTs, Technicolor, SUSY..) Color-triplet scalar (spin=0) or vector (spin=1) bosons carrying lepton and quark quantum numbers Three generations, each coupling to one lepton generation only (lepton number violation, FCNC) LQ Production at Tevatron: dominant q qbar/g g -> LQ LQbar scalar leptoquarks : ( s, m SLQ ) vector leptoquarks : ( s, m VLQ, G, G ) At Tevatron searches are mainly for pair production of Scalar LQ -> CDF VLQ 3 2 +2b (322 pb -1 ) M > 251 GeV (minimal coupling) M > 317 GeV (Yang-Mills coupling) submitted -> D0 : single production of SLQ2 for a luminosity of 300 pb -1 PLB 647, 74 (2007) -> more on back-up slides
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4 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 4 2 nd generation LQ D0 1 fb -1 LQ2LQ2 q q Background : ->W+jets, Z+jets -> ttbar -> QCD : from data Basic Selection : - 1 | | 20 GeV - at least 2 jets | | 25 GeV - MET> 30 GeV (not aligned with to minimize mis-measured MET) - M T ( ) > 50 GeV (to reject QCD background) = BF(LQ2 -> q) Br( LQ2LQ2 q q)= 2 (1- )
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5 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 5 2 nd generation LQ D0 1 fb -1 Optimized cuts (done for m(LQ) = 200 GeV) : - M T ( ) > 160 GeV (W background) - Scalar Transverse Energy S T = p T ( )+p T (jet1)+p T (jet2)+MET>350GeV - M( jet1) > 150 GeV (related to LQ mass) - the jet combination with the invariant mass closest to the searched LQ : |M( jet) rec -M(LQ) gen | < 100 GeV D0 at 95%CL M SLQ2 >214 GeV for =0.5 D0 Data6 Total Bkg6.4 0.7 0.8 Efficiency m LQ =200 GeV 0.079 0.001 0.007 Previous SLQ2 results 170 GeVCDF RunII jj198 pb -1 208 GeVCDF RunII combined jj and jj and jj 198 pb -1 204 GeVD0 RunII combined 294 pb -1
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6 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 6 Search for f* Several models postulate that quarks and leptons are composed of scalar and spin-1/2 particles : -> large spectrum of excited states : e*, *, q* -> contact interactions (CI) between quarks and leptons CDF -> e* (202 pb -1, 2005) -> * (371 pb -1, 2006) D0 -> * (380 pb -1, 2006) -> e* for the first time - production via CI - decay via gauge interaction (e*->e , W, eZ) or CI e*->effbar) Search in ee
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7 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 7 Search for e* D0 1.0 fb -1 Selection : - trigger on single or di-electron - 2 isolated electrons with E T > 25 GeV, E T > 15 GeV - 1 isolated photon with E T > 15 GeV Background dominated by - DY+ -> ee - DY+jet -> ee “fake ” Estimated from ee data Search for a peak in m e Data : 259 events Total Background 232 3 29 events Expected if m e* = 300 GeV
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8 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 8 Search for e* D0 1.0 fb -1 D0 limits at 95% CL m e* > 756 GeV for = 1 TeV m e* > 946 GeV when neglecting CI decays and for = m e* improving previous CDF RunII limit me* > 879 GeV 202 pb -1 Parameters : m e*, (compositeness scale)
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9 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 9 4 th generation quark : b’ ->bZ CDF 1.1 fb -1 4 th generation quark : b’ ->bZ CDF 1.1 fb -1 b'b‘bar -> bZbZ -> bllbqq (l=e or ) Selection : - blind analysis - Z->ee or , p T (z) >20 GeV - N jet 30 3 (number of jets E T > 30 GeV, | |<2) - J T 30 > X ( J T 30 = scalar sum of E T of all jets in the event with E T > 30 GeV and | |<2) Background : Z+jets Predicted from the data by fitting the ET distributions in N jet 30 =1 and 2 and modeling J T 30. 10% uncertainty on acceptance X efficiency (dominated by 6.7% Jet Energy Scale) CDF M b’ > 270 GeV if BR(b’->bZ)=100%
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10 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 10 W’->e D0 900 pb -1 W’->e D0 900 pb -1 Predicted in many beyond-SM scenarios: Left-Right-Symmetric models, GUT models which may also imply SUSY (e.g E_6), … Search assumes : - a SM-like W’ (same couplings). - w’ = 4/3 m w’ /m w w (factor 4/3 if w’->tbbar is possible, i. e. m w’ > 180 GeV) Selection : - isolated central electron (| |<1.1) E T > 30 GeV - MET > 30 GeV Background : - W-> e , - WW, WZ, ZZ, ttbar - QCD background estimated from data (low m T region)
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11 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 11 W’->e D0 900 pb -1 W’->e D0 900 pb -1 Further selection : m T > 150 GeV ->Data : 630 events ->Total Background : 623 18(stat) +83-75(syst) events D0 Limit : binned likelihood of M_T distribution M W’ > 965 GeV
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12 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 12 Search for resonant tbbar production W’ -> tbbar -> Wbbar –>l jj Method : use the single top samples and same W+jets event selection Selection : - exactly 1 lepton (e or ) P T > 20 GeV - MET > 25 GeV - 2 or 3 jets E T >15 GeV | |<2.8 - at least 1 jet with a displaced secondary vertex CDF Limits at 95% CL : Interference W/W’ neglected (m w’ >> m w ) L-handed and R-handed W’ models - if M R < M W’ W’ R can decay to R-handed leptons -> M W’ > 760 GeV -if M R > M W’ -> M W’ > 790 GeV W’ resonances W’-> tb CDF 955 pb -1 D0 : PLB 641, 423 (2006) 230 pb -1 Mw’ > 610 or 670 depending on model
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13 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 13 Z’->ee CDF 1.3 fb -1 Z’->ee CDF 1.3 fb -1 Selection : - 2 electrons E T > 25 GeV at least one in central calo (| |< 1.1) Background : Dominated by Drell Yan (irreductible) Smaller contribution from di-jet, W+jet, W+ , CDF : are excluded at 95% CL Z’ SM < 923 GeV E6 : Z I < 729, Z < 822, Z < 822, Z < 891 GeV
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14 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 14 Gravity is localised on a (3+1)-dimensional brane, the Planck brane, separated from the standard model brane in a 5 th dimension with warped metric. In simplest version : only graviton can propagate in the 5 th dimension Due to the warped metric their wave functions are exponentially suppressed away from the Planck brane (so gravity appears weak) Gravitons appear as KK excitations Parameters of the model : - M1, the mass of the first excitation - the dimensionless coupling to the standard fields 0.01 < (8 ) 1/2 /M Pl < 0.1 (limits : consistency with electroweak data and model remains perturbative) Graviton decays to ffbar and to diboson pairs. Br(G-> )= 2 Br(G->ee) spin G=2 Randall-Sundrum Gravitons
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15 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 15 RS Gravitons G->ee or G-> Selection : - 2 central (| | < 1 electromagnetic objects with E T > 25 GeV Background : - DY and di-photon (PYTHIA) - QCD estimated from data m ee and m combined Example : search Selection : - 2 photons with E T > 15 GeV - m > 30 GeV Background : - SM di-photon (Diphox) - QCD jets faking photons estimated from data CDF 1.1-1.3 fb -1 D0 1.1 fb -1
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16 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 16 RS Gravitons G->ee and/or G-> (8 ) 1/2 /M Pl M 1 limit (GeV) 0.01240 0.1865 Best direct limit to date D0 CDF (8 ) 1/2 /M Pl = 0.1 M 1 limit (GeV) ee alone807 ee+ 889 The area below the dashed-dotted line is excluded from the precision electroweak data CDF 1.1-1.3 fb -1 D0 1.1 fb -1
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17 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 17 RS G->ZZ->4e CDF 1.1 fb -1 Data : 0 events with m 4e > 500 GeV Background : 0 0.02 Signature : Four electron mass peak Discriminating variables : m 4e and 2 Event display of the lowest 2 event
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18 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 18 Arkani-Hamed,Dimopoulos and Dvali LED Events with Large Missing Transverse Energy and one or more jets are predicted in many models beyond the Standard Model : - SUSY with R-parity conservation, - Technicolor (with technirhos decaying into W and Z) - leptoquarks (decay in neutrinos +jets) - Models with compactified LED CDF search ADD MODEL : gravity propagates in the 4 + n dimensional bulk of space-time other SM fields are confined in the 3+1 brane If compactification on a torus, the effective Planck scale M D and the radius R n of the extra dimensions are related by : R n = 1/8 (M Pl /M D ) 2 /M D n If R large enough (O(10 m)), M D could be of the order of 1 TeV Production at Tevatron : q+qbar/g+g G+g, q+g G+q G escapes undetected in the bulk of ED G KK g q q g g g -> topology single jet + MET
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19 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 19 ADD LED CDF 1.1 fb -1 Signature : jets+ MET Selection : - leading Jet E T > 150 GeV - MET > 120 GeV - allow 2 nd Jet with E T < 60 GeV - no 3 rd Jet with E T > 20 GeV Results: Nobs= 779 Nbkg=819 71 mainly Z( )+jets nM D TeVR mm 2>1.33 <0.27 3>1.09 <3.1 10 -6 4>0.99 <9.9 10 -9 5>0.92 <3.2 10 -10 6>0.88 <3.1 10 -11 LEP + MET ICHEP 2004 CDF 95% CL
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20 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 20 ConclusionsConclusions CDF and D0 have performed new (and unsuccessful) searches in many areas for a Lumi ~ 1fb -1 (RunIIa dataset) Not every conceivable model has been probed, but most final states Tevatron, CDF and D0 are performing well Analysis are improving By the end of 2009, Tevatron is expected to deliver 6 to 7.5 fb -1 CDF and D0 have excellent physics prospects before first LHC results !
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21 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 21 Back-upBack-up
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22 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 22 Tevatron is performing very well CDF and D0 experiments have collected more than 3 fb -1 Record Peak luminosity above 2.8 10 32 cm -2 s -1 Peak luminosity
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23 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 23 New @ Run IIa (tracking in B-field) Silicon detector Fiber tracker, preshowers Upgraded @ Run IIa Muon system, CAL Electronics DAQ, (track) trigger system Displaced-vtx trigger p Electronics TrackerSolenoid Magnet 3 Layer Muon System Preshowers p The D0 Detector
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24 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 24 The CDF Detector Addition or Improvments for the Run IIA Si tracker Central drift chamber 4th generation quark : b’ ->bZ CDF 1.1 fb-1 TOF 4th generation quark : b’ ->bZ CDF 1.1 fb-1 Secondary vertex trigger Addition or Improvments for the Run IIA Forward calorimeters: "plugs" (1<| |<3) Extended coverage
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25 Gérard SAJOT PASCOS-07 2-7 July 2007 Imperial College London 25 Recent RunIIa LQ searches at Tevatron ChannelL int (pb -1 )Status SLQ 2 pairs + +2q 105007 Prel. this talk LQ 3 pairs 2 +2b31007 Sub LQ 2 pairs 2 +2q LQ 2 + 2 +q 30007Pub. LQ pairs 2 +2q37006 Pub. LQ 2 pairs 2 +2q29006 Pub. LQ 1 pairs 2e+2q LQ 1 pairs e+ +2q 25204 Pub. ChannelL int (pb -1 )Status VLQ 3 pairs 2 +2b32207 Sub SLQ 2 pairs 2 +2j19804 Pub SLQ 2 pairs +2j19804 Pub SLQ 1 pairs e+2j20004 Pub SLQ 1 pairs e+ +2j20004 Pub SLQ 1 pairs 2 +2q19103 Pub Scalar LQ 1 pairs : comb. 3 analyses above ~20005 Pub. Scalar LQ 2 pairs : comb. 2 analyses above ~20006 Pub. CDF D0 Sub= submitted Pub. = Published, Prel. = Preliminary
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