Sub Z 0 Supersymmetry

1. M.J. Ramsey-Musolf Sub Z0 Supersymmetry Precision Electroweak Physics Below the Z0 Pole

2. Fundamental Symmetries & Cosmic History • What were the fundamental symmetries that governed the microphysics of the early universe? The (broken) symmetries of the Standard Model of particle physics work remarkably well at late times, but they leave many unsolved puzzles pertaining to the early universe • What insights can low energy (E << MZ) precision electroweak studies provide? New forces and their symmetries generally imply the existence of new particles. Looking for their footprints in low energy processes can yield important clues about their character

3. Standard Model puzzles Standard Model successes Fundamental Symmetries & Cosmic History

4. Standard Model puzzles Standard Model successes Fundamental Symmetries & Cosmic History It provides a unified framework for understanding 3 of the 4 (known) forces of nature in the present universe

5. Standard Model puzzles Standard Model successes Fundamental Symmetries & Cosmic History It utilizes a simple and elegant symmetry principle SU(3)c x SU(2)L x U(1)Y

6. Strong (QCD) Scaling violations in DIS Asymptotic freedom R(e+e-) Heavy quark systems Drell-Yan Chiral dynamics Standard Model puzzles Standard Model successes Fundamental Symmetries & Cosmic History It utilizes a simple and elegant symmetry principle SU(3)c x SU(2)L x U(1)Y

7. Electroweak “Maximal” parity violation CP violation in K & B mesons Quark flavor mixing Lepton universality Conserved vector current Radiative corrections Standard Model puzzles Standard Model successes Fundamental Symmetries & Cosmic History It utilizes a simple and elegant symmetry principle SU(3)c x SU(2)L x U(1)Y

8. Atomic transitions & scattering Standard Model puzzles Standard Model successes Fundamental Symmetries & Cosmic History Most of its predictions have been confirmed Parity violation in neutral current interactions

9. W, Z0 bosons • 3rd fermion generation (CP-violation) • Higgs boson (LHC ?) Standard Model puzzles Standard Model successes Fundamental Symmetries & Cosmic History Most of its predictions have been confirmed New particles should be found How is electroweak symmetry broken?

10. Big Bang Nucleosynthesis (BBN) & light element abundances • Weak interactions in stars & solar burning • Supernovae & neutron stars Standard Model puzzles Standard Model successes Fundamental Symmetries & Cosmic History It gives a microscopic basis for understanding astrophysical observations

11. Unification & gravity Weak scale stability Origin of matter Neutrino mass Standard Model puzzles Standard Model successes Fundamental Symmetries & Cosmic History

12. Large Hadron Collider Ultra cold neutrons LANSCE, SNS, NIST CERN We need anew Standard Model Two frontiers in the search Collider experiments (pp, e+e-, etc) at higher energies (E >> MZ) Indirect searches at lower energies (E < MZ) but high precision Particle, nuclear & atomic physics High energy physics

13. Outline SM Radiative Corrections & Precision Measurements Defects in the Standard Model An Alternative: Supersymmetry Low-energy Probes of Supersymmetry New

14. I.Radiative Corrections & Precision Measurements in the SM

15. Weak Decays: Fermi Theory

16. Fermi Theory: QED Corrections QED radiative corrections: finite

17. Fermi Theory’s Stumbling Block: Higher Order (Virtual) Weak Effects Weak radiative corrections: infinite Can’t be absorbed through suitable re-definition of GFin HEFF

18. Re-defineg Finite The Standard Model (renormalizable): Control of Virtual Weak Corrections g g g

19. g g GFencodes the effects of all higher order weak radiative corrections Drm depends on parameters of particles inside loops

20. g g Comparingradiative corrections in different processes canprobeparticle spectrum Drm differs fromDrZ

21. Comparingradiative corrections in different processes canprobeparticle spectrum

22. Probing Fundamental Symmetries beyond the SM: Use precision low-energy measurements to probe virtual effects of new symmetries & compare with collider results • Precision measurements predicted a range for mt before top quark discovery • mt >> mb ! • mt is consistent with that range • It didn’t have to be that way Radiative corrections Direct Measurements Stunning SM Success Comparingradiative corrections in different processes canprobeparticle spectrum J. Ellison, UCI

23. Global Analysis c2 per dof = 25.5 / 15 Agreement with SM at level of loop effects ~ 0.1% M. Grunenwald

24. II.Why a “New Standard Model”? • There is no unification in the early SM Universe • The Fermi constant is inexplicably large • There shouldn’t be this much visible matter • There shouldn’t be this much invisible matter

25. Energy Scale ~ T The early SM Universe had nounification Couplings depend on scale

26. Present universe Early universe Standard Model High energy desert Weak scale Planck scale The early SM Universe had nounification

27. Present universe Early universe Standard Model Gravity A “near miss” for grand unification Is there unification? What new forces are responsible ? High energy desert Weak scale Planck scale The early SM Universe had nounification

28. Present universe Early universe Unification Neutrino mass Origin of matter Standard Model Weak scale unstable: Why is GF so large? High energy desert Weak scale Planck scale The Fermi constant is too large

29. mWEAK ~ 250 GeV GF ~ 10-5/MP2 l The Fermi constant is too large

30. Smaller GF More 4He, C, O… A smaller GF,a different cosmos The Sun would burn less brightly G ~ GF2 Elemental abundances would change Tfreeze out ~ GF-2/3

31. Measured abundances & WMAP SM baryogenesis There is too little matter -visible & invisible - in the SM Universe Visible Matter from Big Bang Nucleosynthesis & CMB Insufficient CP violation in SM

32. No SM candidate Dark Insufficient SM CP violation Visible There is too little matter -visible & invisible - in the SM Universe Invisible Matter S. Perlmutter

33. Supersymmetry, GUT’s, extra dimensions… There must have been additional symmetries in the earlier Universe to • Unify all forces • Protect GF from shrinking • Produce all the matter that exists • Account for neutrino properties • Give self-consistent quantum gravity

34. III.Supersymmetry • Unify all forces • Protect GF from shrinking • Produce all the matter that exists 3 of 4 Yes Maybe so • Account for neutrino properties • Give self-consistent quantum gravity Maybe Probably necessary

35. Fermions Bosons sfermions gauginos Higgsinos Charginos, neutralinos SUSY: a candidate symmetry of the early Universe Supersymmetry

36. SUSY and R Parity If nature conserves vertices have even number of superpartners • Lightest SUSY particle is stable viable dark matter candidate • Proton is stable • Superpartners appear only in loops Consequences

37. Present universe Early universe Standard Model High energy desert Weak scale Planck scale Couplings unify with SUSY Supersymmetry

38. =0 if SUSY is exact SUSY protects GF from shrinking

39. c0 Lightest SUSY particle CP Violation Unbroken phase Broken phase SUSY may help explain observed abundance of matter Cold Dark Matter Candidate Baryonic matter: electroweak phase transition

40. SUSY Breaking Superpartners have not been seen Theoretical models of SUSY breaking Visible World Hidden World Flavor-blind mediation Can we test models of SUSY breaking mediation ? SUSY must be a broken symmetry

41. How is SUSY broken? • How viable is SUSY dark matter ? • Is there enough SUSY CP violation to account for the matter-antimatter asymmetry? IV.Low Energy Probes of SUSY • J Erler (UNAM) • V Cirigliano (Caltech) • C Lee (INT) • S Su (Arizona) • S Tulin (Caltech) • S Profumo (Caltech) • A Kurylov

42. Precision ~ Mass Scale Interpretability • Precise, reliable SM predictions • Comparison of a variety of observables • Special cases: SM-forbidden or suppressed processes M=m~ 2 x 10-9 exp ~ 1 x 10-9 M=MW ~ 10-3 Precision, low energy measurements can probe for new symmetries in the desert

43. = 1 SM Expt Weak decays

44. b-decay SUSY Loops Weak decays

45. kaon decay Value of Vusimportant SUSY Loops: Too small Weak decays

46. b-decay SUSY loops SUSY Weak decays & SUSY

47. Vertex & External leg Drm SUSY Radiative Corrections Propagator Box

48. Flavor-blind SUSY-breaking 12k R ParityViolation Kurylov, R-M, Su CKM Unitarity MW CKM, (g-2)m, MW, Mt ,… APV l2 b-decay 12k 1j1 1j1 No long-lived LSP or SUSY DM SUSY loops Kurylov, R-M RPV SUSY Weak decays & SUSY

49. CKM Summary: PDG04 UCNA

50. Vus & Vud theory ? New 0+ info CKM Summary: New Vus & tn ? New tn !! UCNA