1. DIS2003 A.Tilquin Searches for Physics Beyond the Standard Model at LEP What is the Standard Model Why to go beyond and how Supersymmetry Higgs sector Exotica Summary Andre Tilquin CPPM Marseille

2. DIS2003 A.Tilquin What is Standard Model Three families Three groups One principle Gauge symmetry or local invariance ,Z 0,W ,g m=0 Exact symetry Broken with a Higgs SU(2) doublet Yukawa One observable H 0 Is it working ?

3. DIS2003 A.Tilquin SM results and predictions Not so far….

4. DIS2003 A.Tilquin Higgs mass constraint Higgs is needed by SM

5. DIS2003 A.Tilquin Why to go beyond ? The NuTeV measurement: -ratio of neutral current to charged current reactions in neutrino-nucleon scattering. -When interpreted as a measurement of the mass of the W boson, a 2.9 standard deviations, from the other direct constraints is found. Why not ?

6. DIS2003 A.Tilquin How to go beyond SM New symmetries: -Super Symmetry -New Gauge bosons News Higgs fields: Doublets/triplets New fermions Anomalous coupling, contact interaction Compositeness More exotica: Technicolor Extra dimensions

7. DIS2003 A.Tilquin LEP data set ALEPHDELPHIL3OPAL Per experiments: LEP1: L  175 pb -1 LEP2: L  700 pb -1 Energies: 90  209 GeV

8. DIS2003 A.Tilquin The word of SUSY 01/213/22 l L,R h,H,A H±H± W±W±  Z0Z0 g L q L,R Additional symmetry between bosons and fermions  Associates a SUSY partner to each SM particle G New multiplicative quantum number: R p =1 for SM particle R p =-1 for SUSY particle Conserve LSP stable Pair production ~ Z ~ } }  0 1-4 ~  ± 1,2 ~ H±H± ~ ~  h,H ~ W±W± ~ q L,R ~ l L,R ~ L ~ g ~ G In exact SUSY no new parameters = SUSY should be broken

9. DIS2003 A.Tilquin Breaking down SUSY Its mechanism is unknown: Many models SUGRA (Super Gravity) LSP=neutralino GMSB (Gauge mediated Super symmetry breaking) LSP=gravitino AMSB (Anomaly Mediated Super Symmetry breaking) LSP=wino-like Standard MSSM

10. DIS2003 A.Tilquin Standard MSSM Supergravity inspired minimal models with R parity 1.Heavy gravitino and gluino 2.Stable, neutral and weakly interacting LSP  1 0 Low energy parameters:  Higgs mixing mass term tan(  )v.e.v m A CP odd higgs mass m 1/2 Common gaugino masse at GUT scale m 0 Common sfermion mass at GUT scale A 0 Common trilinear mass at GUT scale (mixing) Production at LEP: All final states characterised by missing energy

11. DIS2003 A.Tilquin Slepton searches e+e+ e-e- ,Z * e+e+ e-e- 2 acoplanar leptons + missing energy Main background from WW  l l Channel  1 0 mass Mass limit Selectron 0 GeV 40 GeV 99.6 GeV 99.4 GeV Smuon 0 GeV 40 GeV 94.9 GeV 96.5 GeV stau 0 GeV 40 GeV 85.0 GeV 91.7 GeV

12. DIS2003 A.Tilquin To compare with Tevatron,LEP results are translated into an exclusion limit in gluino an squark masses Squark an gluino e+e+ e-e- ,Z * q L and q R are mixing  q 1,q 2 Squark missing angle

13. DIS2003 A.Tilquin Chargino and neutralino e+e+ e-e- ,Z * Production at LEP: Decay: W (*) Z (*)

14. DIS2003 A.Tilquin Neutralino Chargino, neutralino slepton and Higgs results are combined. LSP mass limit obtained at high tan(  )

15. DIS2003 A.Tilquin MSSM Higgs Two Higgs doublets: 5 physical states: h,H,A and H  Two free parameters at tree level: m A,tan  =v 2 /v 1 Searches by combining two complementary processes e+e+ e-e- ,Z * e+e+ e-e- Dominant at low tan(  ) Dominant at high tan(  ) Observed limit in the m h max scenario: m h >91.0 GeV (94.6) m A >91.9 GeV (95.0)

16. DIS2003 A.Tilquin Flavor independent Higgs search Some extension of standard model: Two Higgs doublet (type II models), the mixing angle in the CP-even Higgs sector is a free parameters standard decay h  bb or  could be suppressed w.r.t h  cc or gg  Searches for hadronic decay without b tagging. Observed limit for:  =  SM Br(h  hadrons) = 100% m h >112.9 GeV/c 2

17. DIS2003 A.Tilquin Charged Higgs Predicted by 2 HDM models. e+e+ e-e- ,Z * Decays:H   /cs B(H   ) free parameter Main background WW m H  >78.6 GeV/c 2

18. DIS2003 A.Tilquin Invisible Higgs Predicted in different models: In MSSM: h  0  0 Majoron h  JJ Cross section can be different from standard model. Search for acoplanar jets and leptons from Z decay M h >114.4 GeV/c 2 For  =  SM and B(h  Inv.)=100%

19. DIS2003 A.Tilquin Fermiophobic Higgs:h  In some models: Type I 2HDM No couplings to fermions. Coupling to photons through W loop: Anomalous couplings W (*) h   Fermiophobic: m h >109.7 GeV/c 2

20. DIS2003 A.Tilquin Double charged Higgs Predicted by LR super symmetric model (Higgs triplet): Decay in two charged leptons, mainly in tau’s. Yukawa coupling to lepton is free parameter. h  >10 -7 : look for 4  ’s close to interaction point h  <10 -7 : search for kick of charged tracks h  <10 -8 : search for anomalous ionisation OPAL: m H >98.5 GeV/c 2

21. DIS2003 A.Tilquin Anomalous top quark coupling  SM  10 -9 fb Single top production at LEP (FCNC)  Z   R-parity violation l,q W,q e+e+ e-e- t b Delphi

22. DIS2003 A.Tilquin Excited fermions In composite models, fermion & boson are composite with and associated energy scale . Lot of decay channel at LEP: ,Z,W,g f/   e+e+ e-e- e*e*  From differencial x-section gauge group weights factor

23. DIS2003 A.Tilquin Lepto-quark Very similar to excited leptons: New color triplets bosonic fields mediating interaction between quark and leptons (LQ) SpinQF ll Scalar Vector  1/3,  2/3  4/3,  5/3 0,20,1/2,1 e+e+ e-e- ,Z LQ e+e+ e-e- OPAL OPAL Preliminary I3I3

24. DIS2003 A.Tilquin Heavy Leptons One way to explain the mass in the see-saw mechanism New heavy leptons with e+e+ e-e- ,Z L + (N) L - (N) W*W* L ± /N l, L (stable)/l + f

25. DIS2003 A.Tilquin Technicolor Alternative mechanism of Electro-weak Symmetry Breaking: Breaking of global chiral symmetry of technifermions generates Golstone boson used for longitudinal polarisation of massive W and Z bosons. Techniquark condensate replace non zero VEV of Higgs field Need a large number of technidoublets (N D =9) e+e+ e-e- e+e+ e-e- –Vector states  0 T,  0 T   + T  - T or  0 T Technipions couple to quarks and leptons  mass

26. DIS2003 A.Tilquin Extra dimensions Trying to solve the hierarchy problem: Weakness of Gravity at electroweak scale Our word confined to four dimensions Gravity propagates in extra dimensions (ADD) Planck mass Radius of extra dimensions Number of ED Planck mass in ED By choosing M D  EW  No hierarchy problem d=1  R=10 13 mExcluded d=2  R=1 mm d=3  R=1 nm …. d=7  R=1 fmMax in M-theory f,V G 1/M Pl Small but large number of states (G KK )

27. DIS2003 A.Tilquin Extra dimensions (cont) Direct search: missing energy Indirect: look for deviation from (d  /d  ) SM For n=2 M D >1.36 TeV LEP average: M S >1.2 TeV ( =+1) M S >1.09TeV ( =-1)

28. DIS2003 A.Tilquin Conclusions Lot of searches performed by the 4 LEP experiments SUSY: No evidence at LEP and CMSSM fully covered Chargino: m>94 GeV Neutralino: m>45 GeV Sparticles:m>100 GeV Higgs sector: No evidence of non standard Higgs m Higgs  100 GeV/c 2 Exotica: New particles: m>100 GeV/c 2 New scales > 1 TeV New coupling < 10% SM couplings No deviation from standard model, and no evidence of new physics. Hope that something will happened at LHC