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J.-F. GrivazSUSY-06 June 16, 20061 Search for Physics Beyond the Standard Model at the TeVatron Jean-François Grivaz (LAL-Orsay) for the CDF and DØ Collaborations
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J.-F. GrivazSUSY-06 June 16, 20062 Beyond the Standard Model: Enlarge the gauge group Z’, W’ (*) Alternative EWSB mechanisms (TC, little Higgs) (*) Relate quarks and leptons Leptoquarks Extend Poincaré Supersymmetry and include gravitation (Supergravity) Increase the number of dimensions (*) Repeat the history (compositeness) (*) = Not covered today (in 30’) The Standard Model: SU(3) c x SU(2) L x U(1) Y The Higgs mechanism Three generations of quarks and leptons The Poincaré group In a 4-dimensional space-time
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J.-F. GrivazSUSY-06 June 16, 20063 At the TeVatron : p-pbar collisions at 1.96 TeV c.o.m. energy Peak luminosity: > 1.7 E32 cm -2 s -1 Delivered: > 1.5 fb -1 In this talk: 0.2 to 1.1 fb -1 DØ: http://www-d0.fnal.gov/Run2Physics/WWW/results/np.htm CDF: http://www-cdf.fnal.gov/physics/exotic/exotic.html Main Injector Tevatron DØCDF Chicago p source Booster Unless there are good reasons, I’ll pick examples in either one. Still the energy frontier
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J.-F. GrivazSUSY-06 June 16, 20064 New Gauge Bosons
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J.-F. GrivazSUSY-06 June 16, 20065 Extra Gauge Bosons M(Z’-seq.) > 850 GeV (somewhat lower limits in) (canonical E(6) models) M T = M(electron-p T,missing-E T ) M(W’-seq.) > 788 GeV e.g., W’ in L-R models Z’ within E(6) GUTs Beauchemin
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J.-F. GrivazSUSY-06 June 16, 20066 Supersymmetry
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J.-F. GrivazSUSY-06 June 16, 20067 SUperSYmmetry At such a conference, no “What is SUSY ?”, or “Why SUSY ?” Which SUSY ? More or less constrained MSSM, à la mSUGRA neutralino-LSP with or without R-parity violation Gauge Mediated SUSY Breaking gravitino-LSP and neutralino-NLSP Anomaly Mediated SUSY Breaking wino-LSP and long-lived chargino Split SUSY long-lived gluino
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J.-F. GrivazSUSY-06 June 16, 20068 (m)SUGRA Two main search streams at the Tevatron: Squarks and gluinos multijets + missing E T large production cross sections large experimental backgrounds Electroweak gauginos with leptonic decays (Trileptons) low production cross sections typically low leptonic branching ratios clean experimental signature m 0 m 1/2 tan( ) A 0 sign( )
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J.-F. GrivazSUSY-06 June 16, 20069 Trileptons Arise from chargino-neutralino associated production “Golden” SUSY signature but: - low cross sections ( BR) - soft leptons - taus (at large tan ) Needs large integrated luminosity Combine various final states (Also decays via W/Z exchange) General strategy (similar in CDF and DØ): Two isolated (rather soft) e or Require some Missing E T ( ) channel-dependent cuts (e.g. anti Z, ) - An isolated third lepton or track (sensitive to ’s), or - Two same sign leptons Main backgrounds: DY, WW, WZ, W (+ a bit of bb and mis-ID) StrologasHohlfeld
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J.-F. GrivazSUSY-06 June 16, 200610 CDF Analysis Lumi (pb -1 ) Total predicted Background Observd data e e ,e , 710 6.80 1.00 9 +e/ (low-p T ) 310 0.13 0.03 0 ee+track610 0.48 0.07 1 ee + e/ 350 0.17 0.05 0 +e/ 750 0.64 0.18 1 e +e/ 750 0.78 0.15 0 DØ Analysis Lumi (fb -1 ) Total predicted Background Observd data ee+track1.2 0.82 0.66 0 +track 0.3 1.75 0.57 2 e +track 0.3 0.31 0.13 0 SS 0.9 1.1 0.4 1 e +track 0.3 0.58 0.14 0 +track 0.3 0.36 0.13 1 The results of the various channels are combined, “weighted” according to their sensitivity, with overlaps taken into account. Cross-section upper limits & mass lower limits within specific models. Missing E T in +e/ Missing E T p T (3) in ee+track …and in the end…
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J.-F. GrivazSUSY-06 June 16, 200611 m 0 = 60 GeV 2-body decays enhanced ( ) s mixing on ( s L component) decays to ’s enhanced ( ) Models = “favorably tweaked” mSUGRA Both CDF and DØ set m s = m se = m s m(sl) = m( 2 0 ) + only 3-body decays ( ) s mixing off (no s L component) decays to ’s = to e/ ( ) Some work ahead for the TEV-WG…
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J.-F. GrivazSUSY-06 June 16, 200612 Generic squarks and gluinos Strong production ( Large cross sections ) of: sq-sqbar and sq-sq at least 2 jets + missing E T (sq q ) gl-gl at least 4 jets + missing E T (gl qq ) sq-gl at least 3 jets Cascade decays complicate the picture model needed (mSUGRA) DØ three analyses optimized for each of these processes reduces QCD to a negligible level CDF 3-jet analysis optimized mostly for m(sq) m(gl) larger QCD background, estimated from control regions Main backgrounds: Instrumental (QCD multijets with fake missing E T ) (W (missed lepton)+ ) +jets (also from ttbar) (Z ) +jets (irreducible) Martinez Bargassa
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J.-F. GrivazSUSY-06 June 16, 200613 Main analysis cuts: Data cleaning Jet1,2(,3(,4)) p T Missing E T H T = sum of jets p T ’s Lepton veto Angles (jet,missing E T ) Analyses Background expected Events observed DØ 2 jets4.8 4.5 6 DØ 3 jets3.9 1.5 4 CDF 3 jets8.2 2.9 2 DØ 4 jets10.3 2.4 10 H T 225 GeV (m(gl)=240 GeV)
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J.-F. GrivazSUSY-06 June 16, 200614 M gl > 387 GeV (when M gl ~M sq ) M gl > 241 GeV & M sq > 325 GeV You have seen or will see other versions of this plot. CDF vs DØ differences: 371 vs 310 pb -1 tan = 5 vs 3 (little impact) 4 vs. 5 flavors (little impact) Theoretical uncertainty on the signal cross section: CDF includes it as a systematic uncertainty in the computation of the cross section limit DØ reduces instead the theoretical cross section by its uncertainty (more conservative): yellow band …and CDF was a bit lucky. Some work ahead for the TEV-WG…
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J.-F. GrivazSUSY-06 June 16, 200615 st R Stop A light stop can be expected: top-Yukawa impact in RGE First scenario considered by DØ: (relevant as long as m(st) < m(b)+m(W)+m( )) (in SUGRA, needs M1 < M2 at GUT scale) 1 c-jet (soft tag) + missing E T (optimized for various m(st),m( )) Main backgrounds: W/Z+jets + Large L-R mixing stop NLSP and LSP with st c (FCNC) m(st) = 130 GeV m( ) = 50 GeV Bargassa
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J.-F. GrivazSUSY-06 June 16, 200616 Light sneutrino st b l s 2 leptons (+b-jets) + missing E T (s ) (optimized for various m(st),m(s )) Stop exclusion up to m(top) Second scenario considered by DØ: e and final states analyzed Main backgrounds: Z at low mass, top at high mass e analysis: S T =p T (e)+p T ( )+missing E T with two signal examples Stop Bargassa
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J.-F. GrivazSUSY-06 June 16, 200617 Sbottom A light sbottom can be expected at large tan . DØ searched for sbottom pair production, with sb b 1 b-jet + missing E T (optimized for various m(sb),m( )) CDF searched for sbottom from decays of pair-produced gluinos: gluino b sb (100%) 3/4 b-jets + missing E T With 156 pb -1, sbottom masses up to 240 GeV are excluded IF m(gluino) < 280 GeV (and m( ) = 60 GeV) m(sb) = 140 GeV m( ) = 80 GeV Bargassa Martinez
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J.-F. GrivazSUSY-06 June 16, 200618 R-parity violation Possible additional terms in the superpotential: With a term, only RPC pair production, mostly + and 2 0, with (cascade) decays to LSP’s followed by RPV decays e e-e- ~ 0101 ~ 121 e.g. 4 charged leptons + missing-E T With a ’ i11 term, also resonant production: e.g.
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J.-F. GrivazSUSY-06 June 16, 200619 R-parity violation: ijk DØ: 121, 122, 133 considered Three trilepton searches combined: eee/ 0.9 0.4 (background /e 0.4 0.1 (events 0 candidate ee 1.3 1.8 (expected NN -ID validated with Z CDF also used clean four-lepton topologies: 0 candidate vs 0.008 0.004 bg. expected For 133, ee most powerful at large tan and low m 0 : m( 1 0 ) > 115 GeV for tan = 20, A 0 = 0, 0 and m 0 = 100 GeV Autermann
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J.-F. GrivazSUSY-06 June 16, 200620 R-parity violation: ’ ijk DØ: ’ 211 resonant production Reconstruct: m(smuon) = m( jj) m( 1 0 ) = m( jj) No accumulation m(smuon) > 210 to 363 GeV for ’ 211 > 0.04 to 0.10 (tan =5, A 0 =0 and < 0) CDF: ’ 333 pair production Look for ( e/ )( hadrons) +2 jets 2 candidates vs. 2.3 0.5 bg. (Also LQ3) AutermannMartinez
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J.-F. GrivazSUSY-06 June 16, 200621 Neutral Long Lived Particles DØ search motivated by 3 dimuon events in the NuTeV experiment Production and decay model: SUSY RPV with a small 122 Look for displaced dimuon vertices (5 to 20 cm) Calibrate with K s decays 0 candidate vs. 0.8 1.6 bg. Convert NuTeV (p-p at 38 GeV) to DØ (p-pbar at 1.96 TeV) (383 pb -1 ) Autermann
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J.-F. GrivazSUSY-06 June 16, 200622 Charged Massive Stable Particles Long-lived charginos are expected in some AMSB models with a “wino-LSP” (small – 1 0 mass difference) They would appear in DØ as slowly-moving muons Make use of the time information of the muon system scintillators For a 150 GeV chargino: 0 candidates for 0.69 0.05 bg. Gershtein
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J.-F. GrivazSUSY-06 June 16, 200623 Gauge Mediated SUSY Breaking In GMSB, the LSP is a light gravitino G A 1 0 NLSP decays into +G All backgrounds determined from data (fake photons from dijet events, W e + /jet) p T ( ) > 25 GeV Missing E T > 45 GeV 4 candidates vs. 1.8 0.7 bg. “mGMSB Snowmass slope” (N=1, M m = 2 , 0, tan = 15) Signal dominated by 2 0 production m( 1 0 ) > 120 GeV Inclusive search by DØ for + missing E T Gershtein
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J.-F. GrivazSUSY-06 June 16, 200624 Stopped Gluinos In “Split-SUSY”, squarks are ultra-heavy long-lived gluinos Such gluinos form R-hadrons which may stop in the DØ calorimeter. Backgrounds: beam and cosmic muons, measured in data. Strategy: look for a randomly oriented monojet in an otherwise empty event (diffractive trigger). After a while, they decay into a gluon + 1 0 (q-qbar- 1 0 is also possible). (A. Arvanitaki et al., arXiv:hep-ph/0506242) m( 1 0 ) = 50, 90, 200 GeV Excludes gluino masses up to 300 GeV Gershtein
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J.-F. GrivazSUSY-06 June 16, 200625 Indirect limits from B s SM: B s is heavily suppressed SUSY: large enhancement Huge dimuon background Discriminate using Decay length Isolation Pointing Normalize to B + J/ K + Limit at 95% C.L (780 pb -1 ): BR(B s ) < 1. 10 -7 1 candidate event selected in a 60 MeV mass window vs. 1.4 0.4 bg. expected CDF search: Carena GeV
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J.-F. GrivazSUSY-06 June 16, 200626 Extra Dimensions
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J.-F. GrivazSUSY-06 June 16, 200627 Extra-dimensions …come in many flavors: LED, TeV -1, UED, RS Two classes of models considered: ADD 2 to 7 large (sub mm) EDs gravity propagates freely in the bulk KK excitations cannot be resolved RS one 5 th (infinite) ED with warped geometry gravity is localized on a brane other than the SM KK excitations have spacings of order TeV
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J.-F. GrivazSUSY-06 June 16, 200628 Large Extra Dimensions Two main search streams at the TeVatron: Real graviton emission Apparent energy-momentum non-conservation in 3D-space “Monojets” Direct sensitivity to the fundamental Planck scale M D G KK g q q g g g V V f f f f Virtual graviton exchange Modifies SM cross sections Sensitivity to the theory cutoff M S (M S expected to be M D )
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J.-F. GrivazSUSY-06 June 16, 200629 Monojets CDF search in 1.1 fb -1 : Main selection cuts: one high pT jet ( 150 GeV) (soft jets from ISR are allowed) isolated lepton veto Missing E T away from jets Missing E T 120 GeV Main background: (Z ) +jet Calibrated with (Z ll and W l ) + jet QCD is negligible 779 events selected 819 71 expected Beauchemin
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J.-F. GrivazSUSY-06 June 16, 200630 High p T dileptons & diphotons DØ search in 200 pb -1 combines ee and to maximize the sensitivity Still world tightest limits: M S > 1.36 TeV M S >1.43 TeV w/DØ@Run I in the GRW formalism Fit of Data to SM+QCD+LED(M S )
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J.-F. GrivazSUSY-06 June 16, 200631 Randall – Sundrum gravitons Here too, most of the sensitivity is in diphotons (BR = 2 ee) DØ combined ee + as for the LED search doesn’t add much Two model parameters: Mass and coupling ( /M Pl ) For /M Pl = 0.1: M 785 GeV
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J.-F. GrivazSUSY-06 June 16, 200632 Looking for the unexpected
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J.-F. GrivazSUSY-06 June 16, 200633 Signature based searches + X in 0.7 to 1 fb -1 X=e2 vs. 4.5 0.8 X= 0 vs. 0.5 0.1 X= 4 vs. 1.9 0.6 l + Missing E T in 0.3 fb-1 l=e25 vs. 19.8 3.2 l= 18 vs. 15.3 2.2 (CDF Run I excess not confirmed) (Also multileptons + photon) CDF: Goncharov
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J.-F. GrivazSUSY-06 June 16, 200634 Final remarks With a steadily improving collider performance there are still a number of years and fb –1 ahead of us for frontier physics at the TeVatron. CDF and DØ have now begun to explore clearly virgin territories. Already 1.3 fb -1 on tape, only partially deciphered Expect many new results in the coming months
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J.-F. GrivazSUSY-06 June 16, 200635 Back-up Slides
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J.-F. GrivazSUSY-06 June 16, 200636
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J.-F. GrivazSUSY-06 June 16, 200637
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J.-F. GrivazSUSY-06 June 16, 200638 (tree level) (loop) Stop decays in mSUGRA m 0 = 200 to 600 GeV (50 GeV step) m ½ = 110 to 180 GeV (10 GeV step) A 0 = –500 to –1000 GeV (100 GeV step) tan = 3 and 10 to 50 (10 step) Both signs of
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