Search for New Phenomena at Colliders

1. Search for New Phenomena at Colliders Pedro Mercadante LISHEP2006

2. Outline • New physics at TeV scale ? • Supercolliders • Tevatron • LHC • ILC • Conclusions Pedro Mercadante

3. Beyond the Standard Model • We don’t know the EW breaking sector • Neutrinos have masses • Dark matter • Why three generations ? • Does not include gravity! Should be viewed as an effective theory valid up to a mass scale Pedro Mercadante

4. SM Higgs mass • Upper and lower Higgs mass bound as a function of Λ, the scale where SM breaks down Pedro Mercadante

5. Why is TeV scale special? • It is the scale of EW symmetry breaking • We don´t know how masses are generated • In the Standard Model the Higgs mechanism is evoked “ this theory is sometimes dignified with the title `the minimal standard model´, but its is not really a model at all ” Murayama and Peskin(hep-ex/9606003) Pedro Mercadante

6. Hierarchy Problem • Quadratic divergencies for Higgs Mass Huge cancellations to keep its mass at EW scale • Scale for new physics near TeV or ... • New Symmetry that protects the scalar sector Supersymmetry Pedro Mercadante

7. Supercolliders Pedro Mercadante

8. Minimal extension of SM • Pair production of heavy quarks • Pair production of heavy leptons • New electroweak Gauge Bosons • Technicolor • The minimal technicolor model • The Farhi-Susskind model • Single production of Technipions • Pair production of Technipions • Supersymmetry • Superpartner spectrum and elementary cross sections • Production and detection of strong interacting superpartnes • Production and detection of color singlet superpartnes • Composite quarks and Leptons • Manifestation of Compositness • Signals for compositeness in High pt Jet Production • Signals for composite Quarks and Leptons in Lepton pair production Pedro Mercadante

9. Recomendations • Detectors • Detection and measurement of W and Z in their non leptonic decay modes • Missing transverse energy is an important signal. Detectors should be hermetic covering the |η| < 3 region • Ability to tag and measure heavy quarks and tau leptons • Accelerator • 40 TeV collider with L= 1039 cm-2 (1 fb-1) will make possible to explore the TeV scale • For a 10 TeV device the same guarantee cannot so comfortably be made even at a L=1040 cm-2 Pedro Mercadante

10. Past and Future Accelerators Pedro Mercadante

11. Where we stand • Tevatron Run I and LEP • Eletroweak theory tested as quantum field theory at the level of one per mille • Signal for Higgs in global fits? • Top quark discovered with mass of 175 GeV • Quarks and leptons are structureless on the TeV scale • Others (colliders and non colliders) • Neutrino oscilation (and mass?) • BB factors shows CP violation in B0 decays • Flat Universe dominated by dark matter and energy • Tau neutrinos Pedro Mercadante

12. Standard Model Measurements • Several parameters measurements and its SM pull • Higgs Mass from radiative corrections Pedro Mercadante

13. Hierarchy Problem • New Symmetry that protects the scalar sector Supersymmetry • Extra Dimensions • Is gravity at TeV scale? (LED) • Are there new mechanism to protect the weak scale ? (Randal-Sundrum) • Some kind of new physics at TeV? (UED) Pedro Mercadante

14. Chicago  DØ CDF p Tevatron p Antiproton Injetor Recycler Tevatron Run II • Accelerator • pp • 2 TeV • L = 1 fb-1 • Detectors • Hermetical • b id Pedro Mercadante

15. Integrated Luminosity Pedro Mercadante

16. Recent DZero papers topics: Excited states Leptoquark Technicolor Supersymmetry Extra Dimensions Similar for CDF Analysis subgroups: Jets and Missing ET Leptons and Jets Multileptons High pT Leptons Taus New Physics Program Pedro Mercadante

17. LHC (first Supercollider) • Acelerator • pp • 14 TeV • L = 100 fb-1/year • Detectors • |η| < 5 • Jet id Pedro Mercadante

18. Atlas Physics Group B physics Top Standard Model Higgs SUSY Exotics Heavy Ions Monte Carlo Generator Performance Groups e/gamma Jets/ETmiss b-tagging muon Physics Program Pedro Mercadante

19. Acelerator e+ e- Polarized beams Tunable Energy Energy = 0.5, 1, 1.5 TeV? L = 100 fb-1/year Detectors |η| < 5 Jet id Cleaner environment Can we have different (complementary) information ? What can we gain running the two at the same time? ILC (Linear collider) Pedro Mercadante

20. Case Study: Supersymmetry • Symmetry that relates bosons and fermions • Is it related with the EW scale? SUSY must be broken! How to break it ? Pedro Mercadante

21. Two Higgs doublet SM + Superpartners µ parameter Tan  Superpotential Soft Terms Scalar Masses Gauginos Masses Trilinear (A) Parameter Bilinear (B)Parameter The MSSM More then 100 new parameters Pedro Mercadante

22. SM 1 TeV 10 TeV Gauge Unification Pedro Mercadante

23. Problems! • How to make predictions? • If we allow general terms for SUSY breaking there are new contributions to FCNC and CP violation process. Fine tunning again ? How SUSY is Broken ? Pedro Mercadante

24. Typical event at LHC Pedro Mercadante

25. Pictorial View new gauge gauge Messenger Sector Hidden sector MSSM sector gravity Pedro Mercadante

26. mSUGRA Soft parameters at Planck scale. Unification ? Small number of parameters. FCNC supressed. GMSSB: Small Gravitino mass. Soft parameters at Messenger scale. Masses proportional to gauge couplings. FCNC supressed. Consequences RGE equations to evolve soft parameters to EW scale Pedro Mercadante

27. Radiative EWSB Pedro Mercadante

28. R parity conservation ? Lepton and barion number violation The LSP is Stable (DM ?) Pedro Mercadante

29. Signals for SUSY • The LSP is stable and neutral Missing Energy! • At Tevatron energies chargino productions dominates for gluinos heavier then 300 GeV • At LHC gluinos and squarks cross sections dominates up to 1 TeV Pedro Mercadante

30. Tri-lepton signal (Tevatron) • Signal depends on σ X BR Pedro Mercadante

31. Sbotton Searchs (Tevatron) • Model independent if sbotton is light and few particles are available • Need good b-tag Pedro Mercadante

32. The Higgs Sector in the MSSM • Constrained two Higgs doublet model. • 5 physical Higss: h, H, A and H. • The lightest Higgs is necessary light. mh < 140 GeV Pedro Mercadante

33. Pedro Mercadante

34. mSUGRA Phenomenology Parameters: • Common scalar masses (m0) • Common gauginos masses (m1/2) • Tanβ • Common A-term • Sign of μ Pedro Mercadante

35. Baer et al JHEP 06 054 Pedro Mercadante

36. Baer et al JHEP 06 054 Pedro Mercadante

37. Neutralino: neutral heavy stable particle. Good candidate for CDM. In a given framework it is possible to calculate neutralino contribution to CDM. Recent data from WMAP gives: ΩCDM h2 =0.1260.008 We can seewhat are mSUGRA prediction LSP as a candidate for DM? Pedro Mercadante

38. FP Baer et al JHEP 06 054 Pedro Mercadante

39. FP Baer et al JHEP 06 054 Pedro Mercadante

40. Focus Point Region • Squarks masses > 2 TeV • Gluino mass > 1.5 TeV • Is this Natural? Pedro Mercadante

41. Small µ region • Gluino decays mainly in b´s and t´s • Does b tag helps? Pedro Mercadante

42. ILC Reach Baer et al JHEP 0510:020 Mg=1650 GeV Mg=3.5 TeV Pedro Mercadante

43. LHC Measurements • L=300 fb-1 • End point mass distribution • Mass differences measurements • Hint for LSP Pedro Mercadante

44. K. Desch et al studied the chargino pair production at ILC Chargino masse can be measured to be 117.1 (0.1) GeV (scan) Neutralino mass can be measured as 59.2 (0.2) using the decays Bean polarization CM energy scan Will narrow the parameter space ILC Measurements B.C. Allanach et al hep-ph/0602198 Pedro Mercadante

45. Conclusions: • TeV scale will tell us the mechanism of EW symmetry breaking • The LHC will be able to explore this scale • An ILC would be very important to fully explore this scale. It will be important to determine the parameters of several scenarios • From a look at history, LC and Hadron colider synergy are important: top quark, J/Ψ, Z … Pedro Mercadante

46. Pedro Mercadante

47. Monte Carlo Tools Workshop Scheduled for March 20-21 Theoretical physicist Peter Skands uses Monte Carlo methods to decide between the many possible outcomes of quantum interactions.What do roulette and particle collisions have in common? The laws of chance decide--the same input can result in many different possible outcomes. In the former example, the ball can land on one of 38 possible slots; in the latter, the same kind of matter and antimatter can produce collisions that create hundreds of different possible high-energy events. Until each outcome actually occurs, it exists only as a probability. "Monte Carlo tools are a way of simulating particle collisions in full glorious, gory detail," says Peter Skands, a theoretical physicist on the workshop organizing committee. "They take the elementary scattering process and dress it up with all the radiation, resonance decays, hadronization, and leftover beam remnants that are part of a real particle interaction." Such simulations allow scientists to make detailed comparisons between the thing they want to find (such as the signature of a Higgs boson) and the background events that may confuse such signatures. • The Monte Carlo Tools for Beyond the Standard Model Physics workshop on March 20-21 will focus on some of the most exotic possibilities for new physics that theorists consider today. The agenda spans over extra dimensions (your choice of warped, straight, or universal), top partners, and Higgsless models, among others. "I think at the moment we are well prepared to deal with supersymmetry (SUSY); however, that's just one idea among many for what might be lurking there at the Terascale. If it's not SUSY but something else, you want to know you're prepared for it," says Skands. "As the Tevatron collects more luminosity and the LHC approaches, it's important to ask: Are our theoretical descriptions sufficiently accurate? How precisely can the parameters of the new physics be measured? To do this reliably, you need Monte Carlo simulations." Web registration is now closed but people can register onsite the day of the workshop. The program is available on the workshop Web page.— Dawn Stanton Pedro Mercadante

48. Pedro Mercadante