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STANDARD MODEL. The Standard Model. SM contains 19 free parameters (excluding neutrino mass)!. Standard Model of particle physics has many remaining puzzles, in particular:

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  1. STANDARD MODEL . . Steve King, Thursday Seminar

  2. The Standard Model SM contains 19 free parameters (excluding neutrino mass)!

  3. Standard Model of particle physics has many remaining puzzles, in particular: 1. The origin of mass: the origin of the weak scale, its stability under radiative corrections, and the solution to the hierarchy problem (most urgent problem – may be solved by LHC!) 2. The problem of flavour: the problem of the undetermined fermion masses and mixing angles (including neutrino masses and mixing angles) together with the CP violating phases, in conjunction with the observed smallness of flavour changing neutral currents and very small strong CP violation. 3. The question of unification: the question of whether the three known forces of the standard model may be related into a grand unified theory, and whether such a theory could also include a unification with gravity. Steve King, Thursday Seminar

  4. The Origin of Mass Steve King, Thursday Seminar

  5. Origin of Mass in the SM SM Higgs doublet SM Higgs Potential If (why?) and (why?) then potential is minimised by (why this scale?) WLOG suppose 4 d.o.f.3 G.B.s Plus 1 physical Higgs boson Steve King, Thursday Seminar

  6. Hierarchy Problem in SM Note the (tree-level) min cond Including rad corr it becomes Fine-tuning is required if the cut-off • New physics at TeV scale (still the best motivation) • But no hint in precision LEP measurements “LEP Paradox” Steve King, Thursday Seminar

  7. Extra dimensions Technicolour Bottom-up motivation for new physics BSM TeV Supersymmetry Mz The Hierarchy Problem Steve King, Thursday Seminar

  8. Top-down motivation for new physics BSM String Unification M* Supersymmetry Extra dimensions New TeV scale physics Steve King, Thursday Seminar

  9. Supersymmetry SUSY SPIN ½ FERMIONS SPIN 0,1 BOSONS Steve King, Thursday Seminar

  10. Stabilising the Hierarchy in SUSY SUSY implies top =stop leading to cancellation of the quadratic divergence, leaving only log divergence which allows  up to the Planck scale. SUSY stabilises the hierarchy providing: (Also works for gauge boson loops and applies to all loop order due to “non-renormalization theorem”.) Steve King, Thursday Seminar

  11. [c.f. SM ] A nice feature of MSSM is radiative EWSB Ibanez-Ross (s)top loops drive negative MSSM Two Higgs doublets Min conds at low energy  Natural expectation is MZ»» mHu» mstop In fact MZ¿ mstop  FINE TUNING Steve King, Thursday Seminar

  12. The  problem • MSSM solves “technical hierarchy problem” (loops) • But no reason why Higgs/Higgsino mass » msoft the “ problem”. • In the NMSSM =0 but singlet allows SHuHd  <S> Hu Hd where <S>» • S3 term required to avoid a massless axion due to global U(1) PQ symmetry • S3 breaks PQ to Z3 resulting in cosmo domain walls (or tadpoles if broken) • One solution is to forbid S3 and gauge U(1) PQ symmetry so that the dangerous axion is eaten to form a massive Z’ gauge boson  U(1)’ model • Anomaly cancellation in low energy gauged U(1)’ models implies either extra low energy exotic matter or family-nonuniversal U(1)’ charges • For example can have an E6 model with three complete 27’s at the TeV scale to cancel anomalies with a U(1)’ broken by singlets which solve the  problem • This is an example of a model where Higgs triplets are not split from doublets Steve King, Thursday Seminar

  13. The Flavour Problem Steve King, Thursday Seminar

  14. Before 1998 the flavour sector contained 13 parameters Who ordered that ? 6 quark masses, 3 charged lepton masses, 3 quark mixing angles and 1 CP violating phase Steve King, Thursday Seminar

  15. Standard Model states Neutrino mass states Three neutrino mass and mixing . . . . . . . . . . . . Reactor Solar Majorana Atmospheric 3 masses + 3 angles + 1(3) phase(s) = 7(9) new parameters for SM Oscillation phase Majorana phases Steve King, Thursday Seminar

  16. Atmospheric Solar Latest global fit for atmospheric & solar oscillations • Latest version 19th Oct 07 • Latest SSM • SNO salt data • K2K • Latest MINOS results Steve King, Thursday Seminar

  17. Neutrino mass squared splittings and angles 3  errors Valle et al Normal Inverted Absolute neutrino mass scale? Steve King, Thursday Seminar

  18. Tri-bimaximal mixing (TBM) Harrison, Perkins, Scott c.f. data • Current data is consistent with TBM • But no convincing reason for exact TBM – expect deviations Steve King, Thursday Seminar

  19. Useful to Parametrize lepton mixing matrix in terms of deviations from tri-bimaximal mixing SFK arXiv:0710.0530 r = reactor s = solar a = atmospheric Present data is consistent with r,s,a=0 tri-bimaximal Steve King, Thursday Seminar

  20. Neutrinos and the Universe Steve King, Thursday Seminar

  21. Neutrino masses and mixing parameters introduces 9 extra flavour parameters Can the extra parameters help with the creation of the universe? 3 neutrino masses, 3 lepton mixing angles and 3 CP violating phases Steve King, Thursday Seminar

  22. Can neutrino mass help solve some of the problems of the Standard Model of Cosmology: • The origin of dark matter and dark energy: the embarrassing fact that 96% of the mass-energy of the Universe is in a form that is presently unknown, including 23% dark matter and 73% dark energy  many potential solutions involve neutrinos • 2. The problem of matter-antimatter asymmetry: the problem of why there is a tiny excess of matter over antimatter in the Universe, at a level of one part in a billion, without which there would be no stars, planets or life  Leptogenesis •  3. The question of the size, age, flatness and smoothness of the Universe: the question of why the Universe is much larger and older than the Planck size and time, and why it has a globally flat geometry with a very smooth cosmic microwave background radiation containing just enough fluctuations to seed the observed galaxy structures  sneutrino inflation (chaotic vs. hybrid) Steve King, Thursday Seminar

  23. The Problem of Unification Steve King, Thursday Seminar

  24. Standard Model SUSY Strong Weak Electromagnetic Steve King, Thursday Seminar

  25. Howl, SFK Extra U(1)X survives to TeV scale MPlanck E6! SU(4)PS£ SU(2)L£ SU(2)R £ U(1) MGUT SU(4)PS£ SU(2)L£ SU(2)R£ U(1)! SM £ U(1)X M3 RH  masses Quarks, leptons Triplets and Higgs Singlet M2 M1 Three families of 27’s survive to low energy (minus the RH ’s) TeV U(1)X broken, Z’ and triplets get mass,  term generated MW SU(2)L£ U(1)Y broken Minimal E6SSM: Unification at MP E6 broken via Pati-Salam chain Steve King, Thursday Seminar

  26. Howl, SFK Unification at MP in Minimal E6SSM MPlanck MPlanck Low energy (below MGUT) three complete families of 27’s of E6 High energy (above MGUT»1016 GeV) this is embedded into a left-right symmetric Pati-Salam model and additional heavy Higgs are added.

  27. E6 broken via SU(5) chain Right handed neutrinos are neutral under: MGUT E6! SU(5)£U(1)N ! SM £ U(1)N M3 RH  masses To achieve GUT scale unification we add non-Higgs Quarks, leptons Triplets and Higgs Singlets and RH s M2 H’,H’-bar M1 TeV U(1)N broken, Z’ and triplets get mass,  term generated MW SU(2)L£ U(1)Y broken SFK, Moretti, Nevzorov E6SSM: Unification at MGUT Steve King, Thursday Seminar

  28. Blow-up of GUT region Unification at MGUT in E6SSM 2 loop, 3(MZ)=0.118 SFK, Moretti, Nevzorov 1.5 TeV 250 GeV

  29. LHC signatures Steve King, Thursday Seminar

  30. Quarks and Leptons Exotic D,D-bar Three families of Higgs Singlets Right-handed neutrinos Optional non-Higgs from incomplete reps 27’+27’-bar ’ and doublet-triplet problems (absent in minimal E6SSM) Low energy matter content of E6SSM’s . . Steve King, Thursday Seminar

  31. E6SSM couplings DQQ, DQL allows D decay but also proton decay Singlet-Higgs-Higgs couplings includes effective  term Singlet-D-D couplings includes effective D mass terms Yukawa couplings but extra Higgs give FCNCs Steve King, Thursday Seminar

  32. Two potential problems: rapid proton decay + FCNCs • FCNC problem may be tamed by introducing a Z2under which third family Higgs and singlet are even all else odd  only allows Yukawa couplings involving third family Higgs and singletHu , Hd , S • Z2 also forbids all DFF and hence forbids D decay (and p decay) •  Z2 cannot be an exact symmetry! How do we reconcile D decay with p decay? • Two strategies: extra exact discrete symmetries or small D Yukawas • In E6SSM can have extra discrete symmetries, two possibilities: I. Z2L under which L are odd  forbids DQL, allows DQQ  exotic D are diquarks II. Z2B with L & D odd  forbids DQQ, allows DQL  exotic D are leptoquarks • Small DFF couplings <10-12 will suppress p decay sufficiently • but couplings >10-12 will allow D decay with lifetime <0.1 s (nucleosynth) N.B. D/ g2, p/ g4 (this is the only possibility in the minimal E6SSM) • Henceforth assume problems solved by one of these approaches

  33. Athron, SFK, Miller, Moretti, Nevzorov The Constrained E6SSM The Z2 allowed couplings Hu, Hd, S without indices are third family Higgs and singlet, Hu,, Hd,, S are non-Higgs Assume universal soft masses m0, A, M1/2 at MGUT In practice, input SUSY and exotic threshold scale S then select tan  andsinglet VEV <S>=s and run up third family Yukawas from S to MGUT Then choose m0, A, M1/2 at MGUT and run down gauge couplings, Yukawas and soft masses to low energy and minimise Higgs potential for the 3 Higgs fields S, Hu, Hd (even under Z2) EWSB is not guaranteed, but remarkably there is always a solution for sufficiently large  to drive mS2 <0 (c.f. large ht to drive mH2<0 ) Steve King, Thursday Seminar

  34. Athron, SFK, Miller, Moretti, Nevzorov P1 Consider a particular EWSB solution P1 with  = -0.5 P1 P1 Steve King, Thursday Seminar

  35. non-Higgsinos Spectrum for P1 Athron, SFK, Miller, Moretti, Nevzorov non-Higgs Steve King, Thursday Seminar

  36. Note the lightest gaugino states: easy@LHC Gluino » Wino » Bino Steve King, Thursday Seminar

  37. Chargino and neutralino production and decay N.B. Wino productiononly is allowed (no Bino production via W,Z)  Expect N2N2 , N2C1 , C1C1 pair production (not involving the N1» Bino ) However the decays must involve N1 Steve King, Thursday Seminar

  38. Y=N2, N=N1 e.g. N2N2 production and decay Three body decays  M < MZ End point gives mass difference Steve King, Thursday Seminar

  39. Gluinos are light < 1 TeV and easily produced Steve King, Thursday Seminar

  40. SFK,Moretti,Nevzorov Z’ < 5 TeV can be discovered Steve King, Thursday Seminar

  41. Inv. mass distribution SFK,Moretti,Nevzorov Total cross section SFK,Moretti,Nevzorov Exotic D-quarks in E6SSM Usual case is of scalar leptoquarks, here we have novel case of D being fermonic leptoquarks or diquarks Steve King, Thursday Seminar

  42. Novel signatures of D quarks In E6SSM it is possible that the D fermions decay rapidly as leptoquarks or diquarks giving missing energy in the final state However it is also possible that DFF couplings are highly suppressed giving rise to long lived D quarks giving jets containing heavy long lived D-hadron D-hadrons resemble protons or neutrons but with mass >300 GeV: Dp or Dn Clean events with two D-jets containing a pair of stable D-hadrons p p Dp or Dn Steve King, Thursday Seminar

  43. Unified Flavour Models Steve King, Thursday Seminar

  44. Steve King, Thursday Seminar

  45. Steve King, Thursday Seminar

  46. Nothing Steve King, Thursday Seminar

  47. Conclusion • In 1998 Super-Kamiokande discovered neutrino mass and added 9 extra parameters to the SM • In 2008 the LHC may discover SUSY which may add over 100 extra parameters to the SM • Future high precision neutrino and collider experiments such as the Neutrino Factory and ILC/CLIC will hopefully enable a unified flavour theory to emerge based on a smaller number of parameters Steve King, Thursday Seminar

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