Prospect after discoveries of Higgs/SUSY

Yasuhiro Okada (KEK) “Discoveries of Higgs and Supersymmetry to Pioneer Particle Physics in the 21 st Century” November 25, 2005, Univ. of Tokyo

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(1) Higgs Physics

 Finding the mass-generation mechanism for gauge bosons, quarks and leptons the most urgent question of the present particle physics.

 Discovery of the Higgs boson is the first step.

 The answer is most probably related to what is physics beyond the standard model. The electroweak symmetry breaking requires dynamics beyond the SU(3)xSU(2)xU(1) gauge interactions.

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How we have come to understand the strong interaction.

Structure of a nucleus (proton / neutron) Discovery of Yukawa meson Quark model QCD Discovery of the Higgs boson is similar to discovery of the Yukawa meson in understanding the weak interaction.

Weak interaction Higgs mechanism Dynamics behind the EW symmetry breaking

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A Higgs sector is unknown : How many Higgs bosons? (is there any?) What is the mass ?

What is SU(2) representation?

Even if one Higgs doublet model is a good description, What is f ?

What physics determines – m ^2?

What physics determines l ?

Different scenarios provides different answers.

SUSY, String Theory Composite model, Little Higgs model TeV scale extra dimension

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Composite model SUSY GUT a ~10 TeV Extra dimension Various new physics signals are expected in the TeV region, depending on different signals. Gauge force Gravity

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Higgs mass

Large Higgs mass  Large self-coupling  Strong dynamics If we require that the SM is valid up to 10^19 GeV,

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Two interesting cases (1) Low mass Higgs boson (< 130 GeV) (2) High mass Higgs boson (>300 GeV) M.Peskin and J.Wells

SUSY (mh< 135 GeV for MSSM) or Higgs potential is generated at low energy scale (< 0(10) TeV ) Ex. Pseudo Nambu-Goldstone boson mh=100 GeV 200 300 500 1000 Something is needed to be consistent with the EW precision data.

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Higgs coupling

LHC 0(10)% for ratio of the coupling constants ILC A few % for absolute values of various coupling

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Indirect constraint on the heavy Higgs boson mass in MSSM Direct search at LHC Direct search at 1TeV LC ACFA report ACFA Higgs WG S. Kiyoura, et al

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SUSY loop contributions to the hbb Yukawa coupling B(h->bb)/B(h-> tt) is sensitive to the SUSY loop correction to the bottom Yukawa coupling for a large tan b region. B(h->bb)/B(h-> tt ) nomalized by SM value LC LHC K.S.Babu, C.Kolda: M.Carena, D.Garcia, U.Nierste, C.E.M.Wagner

J.Guasch, W.Hollik,S.Penaranda

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Higgs self-coupling measurement

Access to the Higgs potential.

Precision at 1/ab for 120 GeV Higgs boson ~20% for 500GeV ILC ~10% for 1 TeV ILC Y.Yasui, et al, LCWS 02

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Electroweak baryogenesis and Higgs potential Electroweak Baryogenesis First order phase transition Extension of the Higgs sector The Higgs potential at zero temperature is also modified.

=> Self coupling measurement 2HDM S.Kaenmura, Y. Okada, E.Senaha

Model with dim 6 potential C.Grojean,G.Servant, J.D.Wells

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(2) Supersymmetry

 Supersymmetry is a revolution of physics similar to relativity, if it is found.

 SUSY provides a coherent picture of particle physics and cosmology SUSY + GUT => Gauge coupling unification SUSY + R parity => Dark matter SUSY + Seesaw neutrino => Leptogenesis (Baryon number of the Universe) After we confirm the supersymmetry, whether these ideas are realized could be central issues.

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SUSY and GUT

LHC/LC combined analysis SUSY breaking scenario G.A.Blair, W.Porod,and P.M.Zerwas

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Dark matter

SUSY mass and coupling measurements => Identification of dark matter WMAP ALCPG cosmology subgroup PLANCK

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SUSY Seesaw model

Large Lepton flavor violation processes are expected. m ->e g in SU(5) SUSY GUT with seesaw neutrino Slepton flavor mixing T.Goto,Y.Shimizu,T.Shindo,M.Tanaka and Y.Okada.

J.Hisano, M.M.Nojiri, Y.Shimizu, M.Tanaka

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Conclusions

 Discovery of the Higgs boson is the first step to understand the dynamics of the electroweak symmetry breaking.

 Measurements of the Higgs coupling constants can provide hints to new physics.

 SUSY, if it exists, has far-reaching consequences in particle physics and cosmology.

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