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Summary of the Conference

Summary of the Conference. SUSY in 2010s 22 June 2007 Hokkaido University Physics Department and ICEPP The University of Tokyo Sachio Komamiya. Biased History of SUSY Searches. We searched for SUSY since 1980s at PETRA.

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Summary of the Conference

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  1. Summary of the Conference SUSY in 2010s 22 June 2007 HokkaidoUniversity Physics Department and ICEPP The University of Tokyo Sachio Komamiya

  2. Biased History of SUSY Searches • We searched for SUSY since 1980s at PETRA. • Initially slelectrons and smuons and later squarkes were searched for at PETRA in 1980. • In 1982 the first SUSY workshop was held at CERN. • In 1983 SUSY was ‘discovered’ by UA1. • In 1984 Winos and Zinos are searched for at PETRA. • Light gluinos were searched for at beam dump experiments. • Possibility of SUSY searches at SSC/LCs were extensively studied in late 1980s. • In 1990s the analyses were extendend to all the SUSY species; gauginos+higgsinos, sleptons, stop, sbottom, light gluinos at LEPI and LEPII. • Also squarks/gluinos were searched for at TEVATRON. • In 1990s theorists invented many different SUSY breaking scenarios. • The gravitino LSP for GMSB, and cases for small mass difference between NLSP and LSP were studied and they searched for at LEP. • Studies on strategy for SUSY searches at LHC/ILC is going on. • In 2010 we hope SUSY-like signal is seen at LLC. • By 2010 we hope μ→eγdecay is seen by MEG experiment. • In 201X or 202Y SUSY breaking mechanism is hopefully studied at LHC/ILC. • SUSY should be in the Standard Model.

  3. The Revolutionary Epoch • We, particle physicists, hope to enter an exciting epoch in which new paradigm of the field will open by new discoveries expected at theenergy-frontier collider experiments • The Large Hadron ColliderLHC at CERN will starts operating in summer 2008 with the full center-of-mass energy of 14 TeV. Long-waited Higgs Boson and Supersymmetric particles (or new particles or phenomena alternative to these) are expected to be directly produced and discovered. • The MEG Experiment to searchfor μ→eγ will start this year. • Following the LHC experiments, experiments at the International Linear Collider ILC is expected to uncover the underlying physics principal of the new discoveries with precise measurements in its clean experimental environment.

  4. Structure of the Society of Particle Physics Experiments • High Energy Frontier = Regular Army • Flavor Physics = Guerrilla Band • Non-accelerator Experiments = Underground Activities (Theorists = Counselor)

  5. Astrophysics + Cosmology + HEP Astronomical observations and theoretical works have been solving real nature of many unidentified phenomena: Quasars : merge of galaxies (merge of black holes) Gamma ray bursts: Probably type Ic Supernovae Observational Cosmology ⇒ the energy budget of the dark energy and dark matter. We do not know the real sources of these objects. Inflation is expected from the flat and uniform universe, but we do not know how, when, how many times inflation(s) took place. ⇒Synergic studies by cosmologists, astrophysicists and particle physicists are essential to solve these questions.

  6. t 〜1013 sec Formation of atoms Epochs of the Universe t 〜1 sec Big Bang nuclear synthesis t 〜10-10 sec Electro-weak transition t 〜10-34 sec Grand-unified phase t 〜10-45 sec Quantum-gravity phase

  7. Energy budget of the Universe (1) CBR fluctuation (WMAP etc.) (2) Large scale structure of galaxy cluster distribution (3) Type 1a supernovae distribution (4) Big Bang Nuclear Synthesis ΩB = 4.4±0.4 % ΩDM = 20±4 % Ωm ΩΛ= 76±4 % We know only 4% of the universe ⇒ The other 96% must be understood as words of particle physics

  8. Development of Accelerator Technology (75 years of history) Lake Leman Jura Mountains Geneva airport ＣＥＲＮ LHC starts in 2008 with the full energy2r=9km,Ecm=14TeV 9km/13cm = 69,231 14TeV/80keV = 175,000,000 175,000,000/69231 = 2528 = (1.11)75 1932 The first Cyclotron by Lawrence 2r=13 cm,Energy=80 keV

  9. e+e- Collision vspp Collision Higgs production as an example: e+e- Collision Electron and positrons are elementary particles ⇒processes are simple ⇒clean environment ⇒easy to study μ＋μ- Ｚ - e Z - e + H bb pp Collision hadrons p Proton is a composite particle ⇒ processes are complicated High radiation and high background environment ⇒ Needs rad-hard and high-tech detector g t H - g bb p hadrons

  10. Limitation of e+e- Colliders Reactions are simple, the environment is clean… However, Electron looses its energy by synchrotron radiation when bending by B-field Energy loss per turn : ΔE ∝ （E/m）４/Ｒ E：particle energy ｍ：particle mass Ｒ：bending radius Like bankruptcy by loan E,m ２Ｒ Two solutions to have high energy colliders （１）　Use heavy stable particles(Mproton/Melectron=1800）　⇒LHC （２）Ｒ →∞⇒ILC

  11. ATLAS@LHC Diameter 25 m Barrel toroid length 26 m End-cap end-wall chamber span 46 m Overall weight 7000 Tons Detector sensors 110M channels SiD LDC GLD

  12. Pioneers on Higgs Mechanism Peter Higgs Father of Higgs Mechanism Yoichiro Nambu Pioneer of many ideas on symmetry breaking

  13. Acquisition of Mass by the Higgs Mechanism for Weak Gauge Bosons Massless Gauge Bosons Physical Gauge Bosons Higgs Fields w+ W+ φ＋ ＋ W- w- φー ＋ Z0 z0 φ０ ＋ Physical Higgs Boson φ０＊ γ γ

  14. Higgs Boson is driven into a corner of the parameter space Excluded by precise electro-weak measurements Excluded by direct searches at LEP 114 GeV < MH < 200 GeV ~

  15. The cleanest Higgs signal at LHC pp→H＋….. ZZ μ＋μーμ＋μー μ＋ μー μ＋ μー

  16. Higgs Boson @LHC In a few years of LHC running Higgs will be discovered, if the theory is basically correct and the detectors work fine. ATLASS.Asai et al. WWqq→Ｈqq→ττqq

  17. ILC is aHiggs Boson Factory Higgs Boson 5 O(10 ) such events will be collected and studied. Origin of mass Structure of the ‘vacuum`. - - - + + e e Z + H e e + b b To find and to study a fundamental scalar particle (Higgs boson) is the first step to understand Dark Energy and Inflation.

  18. Determination of Higgs Spin H H H Z→q q Z→e e, μμ Z→νν Higgs Event Topology at ILC Branching fraction measurement

  19. Coupling measurements at ILC Self-coupling Top Yukawa coupling Gauge Coupling SUSY Yukawa coupling

  20. Supersymmetry (SUSY) FermionsBosons Supersymmetric partner of electron selectron spin = 0 Wave function of spin1/2 Fermion electron spin =1/2 ・SUSY is a space-time symmetry It plays a crucial role for the unification of forces with gravity Number of extra-dimensions in the string theory is determined ・ Every Elementary Particle has SUSY partner, mass of them　＜ TeV ⇒ The value of the SUSY discovery is that of the Anti-particle ・ The lightest SUSY particle is the well motivated candidate of the Dark Matter ⇒ Understanding of the structure of the universe ～

  21. Ordinary particles SUSY partners Gauginos Ordinary particles Gauge bosons Gauge bosons Scalar Fermions Dark Matter Candidates Leptons and Quarks Leptons and Quarks Higgs bosons Higgs boson Higgsinos Higgs and SUSY are undiscovered Supersymmetry (SUSY) Stabilization of Higgs Boson Mass due to a cancellation ⇒Numbers of Fermion and Boson fields are identical ~ + f f _ h h h h

  22. Grand-Unification of 3 Forces by SUSY

  23. SUSY at Colliders In general, The lightest SUSY particle (LSP) is electrically neutral and does not interact strongly (colorless). The particles with color are heavier than colorless particles (typically Mgluino/Mchargino ~ 3-4) At LHC strongly interacting gluinos and s-quarks can be copiously pair produced⇒SUSY signal can be seen. However, to identify each SUSY particle is not easy. At ILC the light SUSY particles can be extensively studied, once they can be produced.

  24. multiple leptons + high PT jets + b-jets τ-jets SUSY at LHC Multstage cascade decays will be observed Expected event topology :

  25. Polarized (90% e-R) ～ ～ χ0 χ0 Power of electron polarization at ILC SUSY at ILC μ beam μ Scalar muon production & decay Background signal Unpolarized Nakanishi (Nagaoya)

  26. Slepton/Neutralino Chargino/Neutralino Mass, Coupling, Mixing ⇒GUT unification M2 SU(2) gaugino mass M1 U(1) gaugino mass Spin, CP, coupling strength, etc.. are precisely measured

  27. Mass spectrum of SUSY particles ⇒ SUSY breaking mechanism LHC+ILC Combined analysis SUSYbreakingMechanism SUSY particle masses Energy scale Super Gravity (mSUGRA) Gauge Mediation G.A.Blair, W.Porod,and P.M.Zerwas

  28. SUSY Dark Matter Abundance depends on the mass and the annihilation cross section into light particle pair. The density should not overclose the universe, but it should be enough for the formation of the galaxies. If LSP = Neutralino (extensively studied for particular models) Terrestrial searches may observe it, if the interaction cross section σ（χN) is large. Decay of heavy gravitino into the neutralino+light particles may destroy the light elements which were created by the nuclear synthesis. IF LSP = Gravitino (not fully studied) Terrestrial searches cannot observe it, since the cross section is too small. Phenomenology at LHC/ILC is very interesting, especially the NLSP is a charged particle. Dark Matter can be created at LHC/ILC. Detailed studies will be done at LHC/ILC.

  29. The abundance of the LSP as dark matter can be calculated, if the mass and particle species are known. SUSY will be discovered at LHC, and ILC will precisely measure the mass and the couplings of the LSP. ⇒The LSP will be identified and the density of Dark Matter in the universe and in Our Galaxy can be calculated. a(t)3ρ（ｔ） vs time The dark matter particles are gathered by the gravitational force, and galaxies were formed and embedded in the seed-structure made of DM. χχ→ l l ← χχ→ l l χχcannot meet each other LHC/ILC data will give guideline to terrestrial dark matter searches G. Jungman et al. Physics Report 267 (1996) 221

  30. Extra-spaceDimensions Superstring Theory In addition to the 3+1 dimensional space-time, where we are living, 6 extra-space-dimensions exist and they are compactified into a small space size. ξ -33 η • cm • Planck Scale x All the internal quantum numbers of elementary particles are determined by the geometrical structure of the extra-dimensions . (D-brane, M-theory, …, String landscape) Kaluza&Klein tried to unify the general relativity and electro-magnetic interactions by introducing an extra-dimension. The attempt was failed but the philosophy was inherited from them.

  31. Large Extra-dimensions Solve hierarchy problem? Space-time 3+1 dim + n-dim -33 >>10 cm If the size is much larger than Planck scale, the effects can be seen at LHC/ILC The most drastic but untrustworthy signal is a black-hole production. The black-hole decays via Hawking radiation into ordinary particles. e e ＜Schwarzschild radius

  32. Search for extra-space at LHC/ILC K.Odagiri q q - g Massive Graviton emission e+ f G e- f # of extra-dimensional space Massive Graviton exchange The size and number of the extra-dimension may be determined at ILC.

  33. Particle Physics towards 2010s Higgs Boson (has the same quantum number of the vacuum) ⇒The first step to study dark energy and inflation Supersymmetry (new space-time symmetry) ⇒LSP might be the source of dark matter Important clue to Superstring (Gravity, D-brane, black hole) LHC will starts 2008 with the full CM energy of 14 TeV. expected to discover Higgs and SUSY. ILC is hopefully under construction in 2010s. Experiments at ILC is expected to uncover the underlying physics principal of the new discoveries with precise measurements in its clean experimental environment. Probably, something totally unexpected might be discovered at these energy frontier colliders.

  34. Acknowledgements • We thank the local organizing committee of Hokkaido University for the great hospitality and the preparations of this conference as well as a nice weather despite the rainy season of Japan. Special thanks to CEO (chief entertainment officer) of the conference for the right choice of the conference dinner. • We thank all the participants of this conference for their extensive discussions in a friendly atmosphere which is extended to the ILC physicists.

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